To get to my point, ebooks is books. All you have to do to see that is to contrast them with printed books (of which they are merely an analog) and with vooks. With an ebook, you might be using an eReader or a PDA or smart phone, but you are still reading the whole book. With a vook, you stop reading and watch a video. The oddest thing about vooks that I can see is that they are being introduced by publisher Simon & Schuster. That's a little like Weight Watchers giving away Godiva chocolates to new members.
The New York Times recently ran a multi-part blog post asking how the human brain felt about ebooks. It didn't impress me particularly, mostly because the folks being questioned seemed to know a lot about the brain and about reading but not so much about eReaders. One poster did make the comment that reading on a computer was more subject to distractions than reading a printed book or a dedicated eReader, which I thought was significant.
One thing about reading novels is that a good one comes alive in the mind of the reader; most novels don't have (or need) illustrations (although a good cover is essential, even with an ebook). That's one reason why the current crop of e-ink devices are most popular with fiction readers. The screen on my Kindle does well with photos that are optimized for the screen, but not with color photos slapped into the ebook version with no extra effort.
I'll be really curious to see how the new Barnes and Noble eReader works. B&N took an interesting approach. Their eReader has an e-ink screen for text and a color touch screen below it to display menu icons— presumably that includes icons of book covers. Depending on how cheap/easy it is to buy books on this thing, this could be very interesting. But Barnes & Noble selling an eReader still makes more sense to me than Simon and Schuster selling vooks.