for virtuosity and density there's Remarc Thunderclap:
http://www.youtube.com/watch?v=zS3hPo81BKw
for pure beauty, Photek The Rain:
http://www.youtube.com/watch?v=DYsY4wYMQe8
be sure to sit back and listen and wait for the bass to drop ;)
some beautiful mind juggling from Remarc:
http://www.youtube.com/watch?v=1I09dIBsU80
listen to that and try to figure out where your attention is focused. that's not something that fingers do in real time, its like hitting the hyperspace button and writing beats on more than one dimension at the same time. that's tracker music. the software looks like VIM.
Sabar drumming from Senegal:
http://www.youtube.com/watch?v=xWd8n1kK0F0
try to figure out how those beats and changes are structured. Its very precise. They count interesting number series and there are polyrhythms that are very hard to notate in western music.