But I think AT has an edge over the others.. the presentation is more formal (no pics in the posts, everything uniform), moderation, and the all important smaller number of forums.
Sure, you can have a board with a billion posts and 75 million members, but, if you have 100s of forums under which to post, the community falls apart and isnt as tight.. much like the delphi forums site.
Gamespy might be huge, but there is a forum for every game ever made..