I'm the happy owner of an iMac 24'' since a few weeks, so I can tell a lot about laaaaaaarge screens, which have benefits but also some drawbacks.

Over the last years I moved from 14'' to 24'' in steps, also using some 16:9 screens. Bigger monitors allow for more comfort and efficience, whatever the context.

If your're in text editing, you can see whole pages while still having a readable size of text. If you need to work with multiple pages at the same time, this is also easier as you can display them and don't have to constantly switch from one window to the other.

Image editing is also easier as you can display high resolution pictures with a normal zoom factor without loosing the overview and having to scroll all the time. The additional space is also good when working with complex softwares having a lot of small detached windows with palettes, options, and so on.

I also enjoy large monitors for web and applications development, as they make it possible to look at the code and the results at the same time.

If you're an intensive user of instant messaging, a larger monitor will make possible to display your favorite chatting tool beside (and not under) your word processor or web browser.

Last but not least, as nowadays computers can be used to read movies on DVDs, a bigger screen make it better. I've got a huuuuge TV so the 24'' looks a bit "small", but it's certainly good enough !

Beleive me or not, a large monitor has some drawbacks. At first, you need to find a place where it fits. If your desk is not deep enough, you will be too close, and won't even be able to look at the corners of your new screen !

I mentionned above the benefits for web publishers composing new pages. The trap here is to make a new design which look brilliand on your giant screen... and discover later that it is simple unusable on a smaller one because all components of your floaty CSS overlap with each other.

One must also get used to work in "page width" mode, to make the characters big enough. Not doing so will result in leaning forward to be closer to the screen, and this is not really good for the eyes.

Large monitors are good for comfort and productivity. But remember that a computer must be balanced... you can't put all your money in the monitor, or in the memory, or in the hard disk, and sacrify the rest.

Prefer a mid-size screen, disk, memory, CPU, and you will get the most out of your money.