intensemuscle.com - Went there for a few months to learn about DC training. The followers are a little too vehement, quck to flame new guys, and don't leave much room for debate about anything related to DC training. It's either take it or leave it. Don't really go there anymore. Lots of big, smart guys though.
gripboard.com - Best site far and away I've ever seen for grip training. Lots of videos, articles, grip masters, and other stuff to learn from. The only drawback is that no one really talks about anything else, but I think thats the way they like it.
ironaddict.com - Helped me learn the importance of recovery. The first site that really broke it down for me in a way I could accept and understand. Not a lot of chatter going on though, more of a place to learn and just stop by every now and again.
t-nation.com - rarely go there, but every now and again a decent article there is worth reading. Despite most being littered with a ridiculous amount of ads.
irontrybe.com - lower traffic site, but a lot of pure strong guys posting vids and giving pointers. There's a lot of full workouts posted on there from guys moving weights I aspire to, so its a great place to stop in and check out once in a while.
illpumpyouup.com - The guy who runs it emailed me and said he would give me $0.25 per post credit in his supplement store if I came to the board. He also made me a mod. There's a few decent guys over there, but not much of a community. I don't really go there at all anymore, especially since the only supplements i use are whey and vitamins now.
getbig.com, bodybuilding.com - pure comedy