I'm a bit mixed too--or at least for me it depends on the situation.
If I'm not looking for a book right away, or feel like perusing a book store--then the book itself is more important...if I'm looking for a book immediately--then what is available with the click of a button is more important
Also--for travel, the ebook reader makes the most sense. I've been stocking up on books lately for just that purpose, and content has definitely been the driving factor!