FortuneJack seems to be the choice of so many. They offer you 120% bonus up to 250 mBTC and 50 free spins.
The second choice of people wants a bitcoin casino is Cloudbet. They offer 100% up to 5 mBTC deposit bonus.
The third choice is mBit Cansino which offers you 110% up to 1 BTC and a 50% reload bonus.
These are the top online casinos that deal in bitcoins. All of these are excellent and you can check them and and join the one that looks most interesting to you.