(If you've decided on going for an LCD TV, check out my hub Which LCD TV? which tells you what things to look out for when buying an LCD TV)

We'd had an old TV in the house for years and years, but the time finally came for us to buy something flat. And that was about as much as we knew: we wanted a TV that was flat. And shiny. And nice looking. Oh, and not too big, either. And with a great picture.

But which one?

As soon as we began to look, the choice and technology began to dazzle me. Don't get me wrong, I'm technology savvy, but in the case of TVs, I've been quite happy to drift along in the 20th century. The old dinosaur that lurked in the corner of the room like some primeval beast was an old friend, and a reliable one. But ultimately, one that looked and sounded fuzzy compared to some of the new kids on the block. It also took up a lot of space.

I had to be literally dragged away from the electrical store, such was my amazement at the new LCD TVs (I'll explain that in a while) which were 'HD ready' (I'll explain that too in a while!), playing 'Blu-ray' discs (that too I'll explain!). The quality blew my mind. The picture quality looked better than real life, which I found weird and mesmerising.

So true to form, I began to research the details of the different kinds of TVs and TV sizes, and I present you my findings, in the hope that you will find it useful. I don't buy unless I've done my homework. My findings however are only relevant for those of you wanting to buy a TV rather than a computer monitor.

I will also be looking at the environmental costs of these various TVs.

Don't worry, if even my attempt at simplifying things is mystifying, I sum up at the end in even more simple terms...

HD Ready: This means that a TV is able to display High Definition pictures, either from television broadcasts or from devices such as Blu-ray (after a format war, HD DVD lost to Blu-ray).

Blu-ray: blu-ray discs are designed to supercede standard DVD format. They store HD video, and are used for data storage and games as well.

If a TV is 'HD Ready' it means it can display High Definition images from these different sources.

I'm purposely not getting into the numbers of these things (e.g. 1080p resolution), because as you'll see, it's a bit too easy to become over-obsessed with resolution, of an already amazingly high resolution product; though I will be considering a couple of things at the end of this guide.

There are several kinds of TVs in shops these days, which are all competing to provide the best possible image. Though I have read up on the technical side of these products (e.g. for a plasma tv, the picture is created by electricity being passed through tiny cells that are contained between two glass panels, that contain a mixture of noble gases which turn into plasma, which then excites phosphor...) I think it best to avoid all that, and tell you what it means simply!

I'll cover what's different about these TV types, and their main features, before looking at their specific pros and cons.

1. CRT TV (or sometimes known as tube TV)

We all know this one. The dinosaur that crackles with static. However, what people don't know is that the CRT (Cathod Ray Tube) is still probably the best way to display an image on screen. The reason? Tube TVs generally have a better picture quality over newer types of TV on normal television broadcasts (i.e. not High Definition broadcasts), as it's possible to have greater control over the definition of black, and picture contrast. You'll find out that a TV's ability to render the colour black is one of those characteristics that define the general picture quality of a TV; that is, how it handles contrast.

Average screen size is now 28" to 32".

2. Plasma TV

The very first prototype of the plasma TV was actually invented way back in 1964, but it took a while to catch on, due to LCD displays catching on instead. A lot of plasma TVs now come integrated with dvd and home cinema equipment, as plasma TVs generally offer a better cinema experience, due its greater colour range than LCD TV. A briliant guide I found about contrast can be found here: <a href="">http://www.plasma-lcd-facts.co.uk/facts/contrast/</a>, which shows the greater colour depth of a plasma TV. Also, manufacturers are working hard to make black levels on modern plasmas rival old tube TVs.

Plasma TVs are on average about 42" in size, but 70" are also becoming available.

Latest models are HD ready.

Environmental consideration: plasma screens contribute to global warming because of their use of nitrogen trifluride. Plasma screens are also greater consumers of power compared to the old tube TV, as well as the LED TV (see further down).

3. Projection TV

Rear Projection Televisions are the biggest TVs you can get, but are lighter and slimmer than the old tube TVs. They come in three main forms 1) Liquid Crystal Display (LCD) 2) Digital Light Processing (DLP) 3) Liquid Crystal on Silicon (LCOS). Different brands are focusing on different aspects and technologies, presumably to focus on niche markets. The picture quality of these giants is great in darkened and fully lit rooms, unlike the plasma and conventional LCD TVs seen below. The TV uses a bulb that can take 20 seconds to a minute to warm up and cool down. Most projection TVs can display computer signals as well as high-definition and standard TV formats (video, digital and analogue signals). Rear projection TVs are a dying breed however, but good deals can be found on them - especially worthwhile considering since major brands obviously continue providing support for archived products.

These TVs come with very large screens, and in terms of size, you get more screen for your money.

All Sony models are HD ready. There are probably others, but you'd have to read the specs.

4. LCD TV

LCD stands for Liquid Crystal Display, and these TVs have come from the development of flat screen monitors for computers. LCD TVs surpassed sales of Tube TVs in 2007, and are being sold in greater quantity than plasma TVs and projection TVs. The screen uses a system that filters white light to get other colours out (let's remember what we learned at school - all colours are contained in white light!), but this also means that getting a very deep dark over a wide contrast is more difficult. However, manufacturers recognise that LCD TVs will probably become the TV of choice, and so are working hard on this issue of contrast.

Screen sizes typically range between 14" to 65" with larger sets still to come.

Most models are HD ready.

5. LED TV

The term LED TV is actually a misnomer, as true LED TVs only really exist in ultra large screens. However, for home use, it's convenient to think of them as LED TVs, even though they are actually a line of LCD TVs that use LED backlighting. Their main advantage is that they can display a very bright image, brighter than conventional LED TVs. They are very slim indeed, with models on the market just over an inch thick. Also, they actually consume about 40% less power than their LCD parent of equivalent size. Additionally, an imprtant difference is that they offer a wider colour range than conventional LCDs...

Screen sizes are not dissimilar to LCD TVs.

Most models are HD ready.

6. OLED TV

The primary benefit of an OLED display compared to LCDs and LEDs, is that OLEDs do not require a backlight to function. They consume less power during operation. In fact, an OLED is an LED TV whose parts are composed of a film of organic compounds. OLED displays are expected to be more efficiently manufactured than LCDs and plasma displays. OLED TVS far exceed LCD TVs in black levels and contrast, in some cases matching those of plasma screens. Colour also is richer and more realistic. OLED viewing angles are also near-perfect, whereas LCD TVs struggle to keep up with fast movements and tend to blur.

Size commonly up to 55" (so far).

These TVs are obviously expensive, being the latest technology.

1) Tube TV

PROS: Great value for money, good contrast.

CONS: It's huge! A real megasaurus vying for the same living space which you occupy. And I bet you're not reading this guide because you want to buy another one of those...

2) Plasma TV

PROS: Very slick looking, delivering great picture results for DVD discs and HD television broadcasts. Great response time, so no blurry-ness on fast images. Though they're expected to phase out, they provide good value for money in terms of screen size.

CONS: Television signals can display 'picture noise' (that looks like blurred little blocks on the screen). The life time of the plasma screen varies between brand to brand (typically 60,000 hours). Uses as much power if not more than an old tube TV.

http://www.plasma-lcd-facts.co.uk/guide/comparison/

3) LCD TV

PROS: Uses about 50% less power than a plasma. They are ideal for hanging on walls being slim and lightweight, and come with different screen sizes. They are generally quite affordable.

CONS: Colour quality and contrast not so great as a plasma nor an LED or OLED. However, LCD screens have a lifespan of about 60,000 hours, and this is generally longer than a similar-sized plasma TV. However, because LCD screen do dim over time (due to the nature of the lamp), it's worth considering that Sharp makes LCD displays whose lamps can be changed (there may be other manufacturers, but haven't found any).

4) LED TV

PROS: Better and brighter image and less power consumption generally than an LCD. Black levels on the best new LED TVs has improved to plasma like black levels.

CONS: LED TVs can be slightly thicker and more tricky to mount on a wall. LED TVs are more expensive than LCD TVs.

5) OLED TV

PROS: Because these TVs need very little power to operate, in theory their longevity should be greater than LCD or LED TVs. They use less power than LCD or LED TVs. Very wide viewing angles, and better response time (i.e. no blurring on fast images).

CONS: Difficult to see in a bright sunlight. Blue organic phosphor LED has a short life (about 7,000 hours?). The red and green elements could be just as short in terms of lifespan. The first OLED TVs we're seeing in the shops will will be an experiment with regard to longevity... Expensive at the moment, but their price will come down as they become more popular.

You'll notice that specifications talk about the resolution with different numbers, such as 720p and 1080p etc. The truth, however, is that the leap to HD TV is so great, it's difficult to see the difference in images between a screen that displays in 720p or 1080p, especially on a smaller screen. So while it's important not to get hung up on these resolutions, one things which is worth considering, is whether your image source (e.g. Blu-ray disc) and TV screen are matched; or to put it another way, you want to avoid a TV having to scale an image, with slight loss of quality in the process. Therefore, if you intend to buy a blu-ray player, make sure that the TV you buy can deal with the level of source definition (1080i). There's no harm in displaying lower resolution sources e.g. DVD, on a 1080p screen, but there's no improvement either for that matter.

Your choice of TV is ultimately going to depend on how important you think the whole cinematic experience is. If, like me, it's not at all important, I would go for an LCD TV - due to the current price, the size, the engineering durability...

On the other hand, if you want that cinema experience in your own home, you'd probably prefer a large plasma, as their price is reasonable in terms of screen size. But of course, plasmas are known to be the worst for energy consumption and harmful to the environment... And as for the new technologies, such as LED (as we learned actually LCD with LED backlighting) and OLED, these are expensive, as well as questionable in terms of life span (with current manufacturing techniques).

Maybe that is our final consideration. Buying a TV isn't just about going out and spending a load of cash without thinking down the line. What we buy today has an effect what happens tomorrow, environmentally. Having said that, it's worth knowing that leading manufacturers of LCD and Plasma TVs (e.g. Sony, Phillips, Samsung, Panasonic and Hitachi) have 'corporate social responsibility' programs. (Sony for example has a policy of transporting its goods by Rail and Sea rather than Truck and Air, which reduces the transport energy costs.)

A slightly out of date report from ethicalconsumer.org recommends LCD TVs over old tube TVs, for the following reasons: less toxic materials, less electromagnetic radiation and lower energy consumption. It's worth a read as it rates TVs by an ethical score. They score these brands the best ethically: Humax LCD TVs, Loewe LCD TVs, Bush LCD TVs, and Goodmans LCD TVs.

I've had to filter out vast amounts of information for this guide.  And all of my research leads me to the conclusion that I'll buy an LCD TV, probably a 32", as our TV room isn't big... 

I hope that this guide has been of some use to you. If you think I've omitted any important details, or have something wrong, let me know and I'll update this hub. Happy viewing.