ACR and BCP work for me, CA-biased opinion, though..
WPN, Winning Poker Network, includes America's Card Room, ACR, and Black Chip Poker, BCP. ACR is my default online site. In California, WPN is the only option for
online poker that I have played. ACR has the added bonus of providing Cardschat
freerolls, if you are a member of free-roll club at Cardschat.
I think you can play the Cardschat frerolls at BCP.
BCP, since it's owned by WPN, has a lot of similarities with ACR. Not too many outrageous
hands, good variety of games.
It is important to know that WPN sites have cash money games legal in California.
Make sure you read what others have to say about sites that are legal in other US states, and countries.