www.1212.com - Comprehensive music-industry database. Includes listings for nearly every commercial and independent record label, as well as bands and artists, in dozens of countries around the world.
www.pitchforkmedia.com - Informative and up-to-the-minute site for music news and reviews. Be warned: Pitchfork Media reviewers tend to have fairly esoteric and trendy tastes. Their opinions can be overly critical, and their coverage tends to focus primarily on the alt-rock scene. Fortunately, they do know exactly what they're talking about when it comes to music.
www.rollingstone.com - As a magazine, Rolling Stone tends to be a bit out of touch with today's music scene. As a web site, Rollingstone.com stays fairly well in tune. Excellent extras here that you won't find in the magazine, and far fewer attempts at pseudo-New Yorker journalism.
www.spin.com - Home of Spin magazine, often praised as the Rolling Stone for today's generation. Personally, I think it's an apples-and-oranges comparison. Oh well.
(more to come)