Everybody is different.
Personally, I don't buy anything but eBooks anymore, so long as the book I want is available as such. Pretty much the only hardcover I have bought in the past few years is Harry Potter and the Deathly Hallows.
I like the portability. I like having multiple books with me, so if my mood changes I can read a different book.
Most of all, I like that I don't forget to return library books. Library eBooks automatically 'return' themselves so that I don't have to. That, in and of itself probably saves me a few hundred dollars a year.
And if I were to manage to lose my JBL, I still have all my books backed up on two computers and
Dropbox.com so my entire library is protected.
That's me... I have another friend who can't stand reading on a screen, and wants to hold the books. Find for her.
In either case, I suspect that in the long run, hardcovers will be there for the collector, and ebooks will be used by the masses (either on personal tablets or dedicated ereaders or something in between) but the paperback market will be pretty much gone.