You are correct about Ultimate Bet, Sportsbook.com and Doyles room accepting US players.
I started the list with our favorites
SportsBook.com is decent they are on the Cake Poker Network. I actually think
Cake Poker is a better place to play on that network. They treat the players incredibly well, run frequent promotions, and have a cool gold card bonus.
Personally, I don't care for the games on Ultimate Bet too much. Ultimate Bet has a lot of Props (props is short for proposition players and they are paid a fee by the house to keep the games going) and the games seem much more difficult to beat than they should be.
I haven't played on Doyles room, since they have moved networks again

.
Thanks for the input though, I will update the list.
Jason