For me personally I don't think anything will ever replace the feel of a real book but I concede there are some advantages to reading electronically and they are as follows:
E-readers are environmentally friendly - No trees need be sacrificed for an e-book, however, the worst thing is knowing how many books are thrown away with gay abandon!
Text can be enlarged to a comfortable font - think of the savings on cheaters!
You can buy books almost immediately - this might be a curse? Instant buyer remorse anyone?
You can lighten or darken the screen according to the conditions - no turning on the bedside light and disturbing the snoring spouse who is probably disturbing you which is why you are awake in the middle of the night reading.
They are lightweight and portable - I'm looking at you, War and Peace. You can take 100's of books on vacation with you, of course why would you want to?
You can carry them easily in a purse or pocket - very handy for waiting rooms where the most up-to-date magazine is 1987 Family Circle.
They are probably more sanitary than a pawed over library book - let's have a Gordon Ramsay Hotel Hell black light on them - yuck!
No bookmarks required - some people use odd scraps of paper, or, horror of horrors, they fold down corners on books!
The e-reader cover hides what you're reading - why should that be an issue for you? Hmm....
A lot of e-books are cheaper than the printed versions - Did you know you can buy the entire Tarzan of the Apes collection for $1.99? - how do I know that?....someone told me, honestly!
You can add notes and highlights without defacing anything - I am a bona fide defacer but I use pencil to do so. Does that count?
Future museum artifacts?