In essence, the two formats are very similar. Both allow you to do the most important thing - read a book. The text is the important thing, not the medium. Reading Sumerian legends on clay tablets can feel more "authentic", but doesn't necessarily enhance your understanding of the subject matter - just your experience.

Depending on the type of material you'd like to read / look at, however, one does have advantages over the other.

Paper books offer multiple advantages:

• They're easily obtainable (Bookstores are everywhere).
• They're easily portable.
• They don't normally cause significant eye-strain.
• They're cheap.

Okay, that much was obvious. Specifically, some types of content paper books are better for are:

• Textbooks (or any books which are generally large-format).
• Picture / Photo books.

Another factor to bear in mind is that paper books don't need power to function. They can be read anywhere with sufficient light, and are perfect travelling companions for exactly this reason.

The obvious cons are:

• Paper books are bulky and heavy. Carrying more than 2-3 around can become a chore.
• You need a light source to read them - another thing that you'll probably carry around.
• If you make notes in them, those notes are there to stay (Yes, even pencil. You can always see the imprints, even if you erase every last shred of graphite).

eBooks offer the following obvious advantages (assuming you have an ebook reader):

• They're easily readable. Most readers offer zoom functions, letter resizing, and so forth.

• They're easily portable. You can carry multiple books on one device.
• They're much more environmentally friendly. You don't have to kill a few trees for each book, and let's not even talk about the ink. Recycling only goes so far.
• Note-taking is much more powerful, and the notes you write can be found and referenced quickly and easily. And they don't have to be permanent.
• Lighting conditions essentially become meaningless. Many readers incorporate display lighting allowing you to read whenever and whereever you like.

eBooks are useless without a reader. There are a few on the market, such as Amazon's Kindle, Jinke's Hanlin reader series, Sony's eReader series, and a few others. These are mentioned because they incorporate a technology called e-ink, which resembles paper very closely, and eliminates most eye-strain issues.

Some types of books especially suited for a reader are:

• Novels or non-fiction books without many pictures.
• Web-sites with html links and cross references.

The disadvantages of ebooks generally stem from the hardware you're reading them on. If it's a computer, you've got the normal computer problems which detract from your reading pleasure:

• Eye strain and RSI. Long periods spent in front of a computer are healthy for nobody.
• Power. Your average laptop has 4-6 hours of battery life.
• Portability. Why lug a laptop around if you can simply carry a book?

The cons of the reader devices are a little more subtle:

• You still have battery life to worry about.
• Nasty software bugs in the reader can cause it to freeze up.
• They're not very robust. If you spill <insert beverage of choice> on them, chances are that's the end of your reader. Not to mention scratches, dropping them, and so on.

In general, ebooks suffer from other cons as well:

• They're not readily available, and format wars are making the decision to buy a reader very difficult. Will you go for the Amazon one, and buy books (only) there? Or the Sony?
• The pricing model hasn't been worked out yet, causing some major discrepancies.

Personally, I mix and match. I have an old Palm pilot, and read novels, websites, blogs, and so forth on that. The selection of novels isn't very broad, but as I read public domain books most of the time, this doesn't really matter as I can simply download them.

Paper books are still my favorite though. They don't need batteries, and I can read them just about anywhere.

Time will tell whether ebooks are a viable alternative. At the moment, the whole thing is still in it's infancy, and a decent solution has yet to appear.