Music Essentials

This is what I use to procrastinate or keep me entertained while I clean my room on a Saturday night.

SomaFM
Internet radio, live from somewhere in the Haight? I particularly like the Secret Agent station

Internet radio stations tailored to you taste:

Last.fm
Must register (very quick, easy) and install a small, simple-to-use program to listen.

Pandora.com
Uses a mildly annoying Flash interface, but it allows you to listen immediately.

Type in a few bands/artists you like, then sit back and enjoy. Here's a review/comparison sort of thing:

Pandora and Last.fm: Nature vs. Nurture in Music Recommenders