Actually all this depends upon your recuirments to gambling way .
I my self like the three sites to gamble .
first site is nitrogensports.eu second is cloudbet.com and third is directbet.eu .
These sites have fascilty to gamble bitcoin in evry possible games . The first two are my best gambling sites becase we need once deposit the bitcoin in the created account  but opposite of  this we can make direct bet withoout creating account at all . We can dirtect select bet and place our bet by the bitcoin the given adress .
so just choose the best gambling site according to your need .