I'm personally a big fan of roulette and slots and I look for casinos that allow me to use relatively small bet sizes (around 0.001 BTC).
If there's a progressive jackpot, that's also a big plus for me, especially if they don't require huge bets to be able to win it.
So let me hear what you are looking for in online Bitcoin casino's...
First online casino when I look is quoted and reviewed from some trust users on blogs or forums. I will try playing with small account and try to cashout. If cashout is easy & quickly, I will repeat more than 3 times. If not problems I will increase my balance and enjoy to play.