I am a big fan of this so here's my favorites list:

8 Bit Weapon: http://www.8bitweapon.com/music.htm
ALICEFFEKT: http://www.jamendo.com/en/artist/Aliceffekt
Brentalfloss: http://www.brentalfloss.com
D+D Sluggers: http://ddsluggers.com
I Fight Dragons: http://www.ifightdragons.com/
LukHash: http://www.jamendo.com/en/artist/SH_MUSIC_%28lukhash%29
Machinae Supremacy: http://machinaesupremacy.com/videos/
Minibosses: http://www.minibosses.com/
Powerglove: http://www.vgmetal.com/indexNEW.php?page=music
Pornophonique: http://www.jamendo.com/en/artist/pornophonique
Vomitron: http://www.myspace.com/vomitron





and I will add more as I remember or find them...enjoy