Everyone wowed about NCSU, how about HCPL's Aquabrowser implementation?
(pointed out in e-mail from CSB) It's from TLC, and it appears to rock. On the LHS it's got a visualization of the subject and on the RHS it's got facets. Well, it's just plain pretty. And yes, it rocks.
Update 2/17/2006: HCPL - Howard County (Maryland) Public Library. The title of the post is hyperlinked, but I'll repeat it here: http://aquabrowser.hclibrary.org/aquabrowser/ . Also, on the TLC web page there is a list of libraries (http://www.tlcdelivers.com/aquabrowser/customerlists.asp?type=ab) who have purchased the technology. A few, so why haven't I seen this in the biblioblogsphere yet?