Zoomii.com is a nice completely javascript version by a friend from a canadian startup. Focused completely on books. Zoomii's really impressive. Its speed makes google maps feel slow.
I wish I could see my Amazon wishlist with that interface, Amazon's UI for the wishlist is terrible.
Zoomii deals with a total of less than 200k items in its inventory compare that with how many geocodes and frames are necessary to represent a street chunk.
Having said that, here are some reasons why I prefer Amazon's usual interface:
* Used book prices
* links to other editions (including Kindle, audio, etc.)
* "Customers who bought this item also bought" (with ratings) -- I use this to get a quick grasp of the popular titles in any given genre.
* The customer ratings, which are of course being gamed these days, but which continue to provide additional perspective in some cases.
And, of course, what this is really missing is the ability to open up the book and page easily through it. That's the real killer app for a physical bookstore, and zoomii seems to have less of it than Amazon.com, not more. Amazon offers "Look Inside" for many books, which I don't think is really a great substitute for looking inside a physical book, but it's better than nothing.
Is Amazon's interface cluttered? Yes. Is it so cluttered that I'm willing to give up these bits of it in exchange for less clutter? No.
It's fast that's the main thing. As long as it works that fast, I think there can be practical applications