I like Ask A Mustachian for the case studies and other advice-seeking. Investor Alley is not my cup of tea, but if you're into that, there's a lot of knowledgeable people over there. Off-topic has a lot of political arguments. Share Your Badassity is good for inspiration. Antimustachian Wall of Shame and Comedy is good for those days you feel snarky or need feel superior.
ETA: If you sort by "show unread posts since last visit" rather than by sub-forum, you'll always get the most "active" threads.