IN Clan : Tillerman, winner of the beta ladder, is a member of this clan, full of strong players. Their website has good commentary, replays, links, and news. Each news posts has a link to a page with comments and replies from their community, although many of the posters are flaming idiots. I'm talking Short Bus here. However, there's always a good debate going on, and some insight into the minds of high-level players.
WarcraftStrategy.com : links to news, replays, commentary, reviews, opinions, interviews, and (yes) strategies. A great place to pick up some tips and hints for play, and to check on new items here and there throughout the wc3 community. I check this page every day just to see what has shown up on the web in the past 24 hours, to make sure I haven't missed anything good.
BattleReports.com : some excellent battle reports, complete with commentary, screenshots, and (in the better reports) lots of humor. A fun way to kill time!
Blizz-Craft : great place for replays.
Expect Nothing! : specifically, their replay page. Good collection of replays.
ProGamer.ru : more good replays.
Expect Nothing! : specifically, their replay page. Good collection of replays.
WCOnline : general news site.