Unixhelp:Audio
While it's an ecclectic EFnet IRC channel, some of the favourite sites for streaming music are:
Trance/Techno/Beats - tchang, cyberfrg
Rock - Hawson
Progressive/Acid Jazz - Yashy
Jungle - staaka
80s - Yashy
underground/alternative - RndPkt
trance - cstone
synthpop/industrial/80s newwave/uk punk - cstone
rap/urban/hiphop - cstone
From the Top - Classical music performed by very talented kids - Hawson
Sometimes, you don't want music, but something else:
Wait, wait, don't tell me! - Very funny "news quiz" radio show from WBEZ in Chicago. - Hawson
Midnight Special - Folk music with a sense of humor - Hawson
CKLN 88.1 Toronto radio station with mandate to represent those with no voice in mainstream media (homosexuals, communists, various cultures, antis) Can be disturbing.- pbug