I'm interested depending on pricing. I rarely every re-read a book--and have yet to re-read an e-book (will buy the hardcover for something like Lord of the Rings that I do re-read periodically).
So if it's cheaper, I'd be for it. Though I do worry about battery life a tad--but then again the iPad gets 10 hours with wifi on, and apparently 9 for the 3G version with 3G connected, and those battery lives are fine with me as I've never read close to that much in one day in my life. And I don't mind plugging in a device every night or two to recharge.
Only downside is reading on a plane etc. So I'd prefer more of a rental system with temporary downloads for a monthly fee etc.