re: Poker & 500.00 BR,Limit holdem question.....
300BB is the often quoted amount. If you can replenish your bankroll with money outside of poker, 300BB or even 200BB is fine. If you want a self-sustaining roll, then 500BB is a better choice. I've had many 50+ BB wins as well as 50+ BB losses in single sessions. It doesn't take much for a long downswing to eat through 150BB.
It also matters if you are willing to step down limits or not. If you are playing on a shorter roll, you should be more willing to drop down a limit (so you have 300BB+ for the new limit).