I've had pretty good luck with the Amazon recommendations since I updated my own book history. I didn't put in all the books I like, but I did pick some particular favorite authors and rate several of their books each. Amazon kept recommending Jonathan Stroud's
Amulet of Samarkand, for example, which I resisted buying until I came across a copy at a library used book sale. It turned out to be a favorite (so I've read it several times since then, plus the two other books in the series). I've paid a bit more attention to the Amazon recommendations since then, and while they're not all spot-on, they're not bad.
Of course, librarything can do that, too.
I do like browsing the "new in Science Fiction" shelves at my local book stores, and I suppose if Borders had something similar, I might give it a look. But in a book store I can read several pages if I want to. If Borders doesn't offer that, I don't think I'd like the interface at all.
(And yes, Flash is an utterly inappropriate technology for any retail site.)
Edit: Regarding Taylor's excellent proposal, it's funny, but I just finished writing up something like that as part of a research paper for a graduate education class....