Since the unfortunate demise of mp3.com, I haven't really found anything else that let me stream lots of decent new music. I guess they're trying to resurrect the site as Download.com Music, but it's so lame compared to the old site: no streaming mp3s, no top-music lists, no user stations, individual downloads only (instead of being able to listen to all the songs from one artist).
I was looking at the the Epitaph site for the Weakerthans and realized that I could make a playlist from the free songs on the Epitaph site. There's tons of great music on there from Pennywise, Millencolin and a bunch of others that I hadn't heard much about. If you like punk, pop-punk, and general guitar rock, you'll probably like this mix:
m3u Epitaph Playlist
b4s Epitaph Playlist
pls Epitaph Playlist
Actually, this WebJay playlist is much better because it gives you all the song titles, direct links to download the songs if you like them, and you can play them in almost any kind of player...plus I put some better songs in there.