For bankroll requirements, you need to consider if your bankroll is all you have for poker, or if you lose it all, your just going to reload.
For playing with your poker bankroll and that if you go broke, your quitting poker or getting a job to start a new bankroll, I would recommend:
500 bb for limit
50 x max buyin for no limit games
50 x buyin for sng's
100 x buyin for tournaments
If you go broke and your just going to reload, I would recommend:
250 bb for limit
25 x max buyin for no limit games
25 x buyin for sng's
50 x buyin for tournaments
You want to make sure you don't feel the loses, yet some people may need close to 1000bb for limit so losing doesn't put them on tilt or effect their play. Those are the guidelines that I've been using, but everyone is different. Find your comfort zone.