I know, I know. I got most of these sites from other people. But, nevertheless, I feel compelled to make a list, and since I thought of this while I was visiting all these music sites, here. we. go!
Popmatters: even more than just music! Good for reviews on lots of subjects.
Better Propaganda: Used to be good for downloading lots of MP3s... now, not so much. (Don't know what happened.)
Pitchfork Media: Lots of reviews (not all of them are pretentiously snobby...), lots of good updates on what's going on.
Epitonic: Music, music, music.
Insound: More music.
All Music Guide: Comprehensive. Good for finding quotes to put in FSView articles.
Purevolume: DIY, DIY. Check out that band, Letters to the Editor. A lot of bands have a slew of songs here (Less Than Jake, Pedro the Lion, etc.).
And, the obligatory weezer sites:
Weezer World: Some coolguy teenager's list of tons of Weezer songs (most unreleased, but also some B-sides). Even songs from Rivers' previous (metal) band, Avant Garde. Ch-ch-ch-eck it out. I would recommend "I just threw out the love of my dreams," "Blast Off!," "Hey Domingo," "Saturday Night," "Sugar Booger," "Teenage Victory Song," and "Thief, you've taken all that was me" for starters. Of course there's no reason you shouldn't listen to all of them...
Weezer Nation: Enourmously large media section. This, is, just, awesome.
And there you go. That should comprise an entire weekend's worth of musical entertainment. Easily.
Any more good music sites (not really interested in p2p now) out there? Lemme know.