I also live in California (San Diego area), so I am quite familiar with situation for CA residents. The casinos that were mentioned earlier -- Golden Palace, Starluck, and Planetluck -- do not allow CA residents.
Most of the best available bonuses are Microgaming Clearplay/eZ bonuses. You can read more about them, including average gain with various strategies, at
http://www.beatingbonuses.com/clearplay.htm . In my opinion, the 10 best reputable bonuses that are available are:
1. Lucky Nugget -- 400% Clearplay up to $200
2. All Jackpots -- 450% Clearplay up to $225
3. Vegas Palms -- 400% Clearplay up to $200
4. Yukon Gold -- Riskless 100% of loss refund up to $50
5. 7 Sultans -- $500 Freeplay with up to $200 bonus winnings
6. Casino Classic -- $500 Freeplay with up to $200 bonus winnings
7. Blackjack Ballroom -- $500 Freeplay with up to $200 bonus winnings
8. Captain Cooks -- $500 Freeplay with up to $200 bonus winnings
9. All Slots -- 350% Clearplay up to $175
10. First Web -- 400% Clearplay up to $100
Among these casinos, I expect Belle Rock group to pay the fastest, usually 1-2 days. Casino Rewards and Fortune Lounge groups should be on the order of three days. Jackpot Factory group has been having some issues recently, and is unpredictable. I had a Jackpot Factory cashout on Saturday that arrived 3 days later; but a few people have had much longer delays for inconsistent reasons.
Among non-MG/Clearplay bonuses, the reputable sites with the best bonuses tend to be the ones that do not allow US players. A noteworthy exception to this generalization is Golden Casino. It is not as reputable and does not have as fast cashouts as most of the MGs; but better than the Parlays, Powerbet group, or Virtual group.
The link in my signature gives a more complete list and more detail. Be sure to read the Casino Rewards and Fortune Lounge warnings about claiming multiple bonuses in these groups without non-bonus play in between.