www.xpn.org
This radio station is doing the 885 greatest music albums of all time, and it just hit the top 5. You can listen live if you'd like, though they don't play the whole albums due to copyright issues. You can see the whole list, too.
It's sorta biased due to the type of music the station plays, but I thought it was sorta cool.
Edited, Mon Oct 17 15:41:31 2005 by DodoBird