[mindcrime]

Do you like classical music? If so, there are plenty of shoutcast streams out there with classical with no vocals. There's also plenty of electronic music (some techno, some trance, etc.) with no vocals, that you can find to listen to.

[adam0101]

Rock, some elctronica, and hip hop would be ideal. I'm more into indie rock, stuff like company of thieves, band of skulls, the hush sound, jack's mannequin, etc. Although I can listen to some electronica like mgmt and can also listen to some hip hop.

[insipid]

Can't help with the rock/hip hop, but for electronica (and its ilk) I would recommend: soma.fm (or, apparently, somafm.com, now.)

(For example, the "cliqhop/idm" shoutcast stream is what I use when I need non-distracting music in the background, for working.)