Russell,
My local bookstore has a Sony e-reader on display and I was seriously contemplating buying it. Yeah, it looks great. But I did some research, and its definitely not worth the money [IMO]. Unless you have that kind of cash laying around with no use for it, I'd recommend not buying one, mainly because [1] the price will come down appreciably in the not too distant future, [2] compatibility is an issue - all those free pdf files may or may not be convertable to the reader, and the quality of the conversion is an unknown, [3] for the Sony, at least, operating it was counter-intuitive and [4] the Sony did not have a back-lighting feature, which I wanted. And, it looks great, but it doesn't look any better than a real book.
These were my reasons for not buying one. I ended up getting a handheld instead - I didn't save any money this way, but I got a lot more for my money. I use it for work, but also I can easily download and convert pdf books [and other formats, such as docs], I can read at night without turning on a light, and I can write with it [a large part of my first novellette was written on the handheld]. If you just want to read books, a handheld isn't a good buy for your money, but if you have other uses for one, then I'd recommend using that to read your e-books rather than buying an e-reader.