First of all, it's definitely not Alexis Texas! Her ass is nothing but fat. Looks good only when she's sitting on a cock from behind. Otherwise, a big no no.
Honestly, I don't think asses are pornstar's best assets. If you really want to see a nice butt, go see a women volleyball game.
But if I really had to pick some, I would say Eva Angelina is a way to go.