Any damn person he wants. But I voted GSP, because he deserves a super fight of some sort to finish of his career. He's the best MW fighter ever, and will still likely be known as such, for the next 5-10 years (retired or not). He's undefeated in the UFC, on a 16 fight win streak, and 2-0 in the LHW division. He's earned a fight that would make him big money, to finish his career.