Web Trend Map
The Information Architects from Japan have put together a very nice visualization map of the 300 most influential websites. To create the mashup, IA took the sites and pinned them down to the Tokyo area train map. I had been playing with version 2.0 for a little while, and they already have the new, updated 3.0 version. The key change on V3 is that they featured the most influential websites - regardless of category.
Check out the clickable on-line version with live links to each site.

Version 2 was a layout of sites based on category.

All the V2 details are on the IA site.
Visualizing complex networks is challenging and the folks at Visualcomplexity.com are striving to be the one source place for anyone looking for information on the subject.