Mine has been Elanya with Domino a fairly close 2nd.  However, I am thinking about giving either Corine or Brianna a try.

Go check out Marilyn!  She is not a young thing, but she more than makes up for it in oral skills, attitude, and enthusiasm.  I think she is up for just about anything...greek, bbbjtc, 3 way, foot work, etc.  Susan was also a favorite, but on the other spectrum...young and beautiful, but also sweet and accommodating.