Well, I finally have my hands on one, and I have to say that the thing is absolutely beautiful. (And I have to say that by "have my hands on one," I mean that I'm standing here at the Apple store playing with one.)
The interface Is clean and smooth, and the web looks absolutely gorgeous. The books look great too. This keyboard is a whole lot better to use than my iPod touch's, though not a reasonable substitute for a laptop keyboard.
I think I can live without one, at least as long as it remains primarily a media consumption tool, as opposed to a media creation tool. My MacBook wins this round.