My 30 closest Last.fm neighbours by country. Excludes those who didn't set a location. Males in blue, females in red. Dots in the same country are spread out randomly for the sake of visibility; there's no data on whether US neighbours are actually on the East Coast or not, for instance.
The map probably says a lot more about where Last.fm is being used than about where people with similar tastes are located, but still. Made using pylast and Google Fusion Tables.
http://thesoundofspiders.net/fb-posts/lastfm-map.jpg