Stannis, naturally! His black-and-white personality would normally be a turn off for me, but he's the only character who has consistently worked for the good of his realm, and has proven his intelligence and valor many times over.
I don't dislike Dany, but if she were really determined to claim the throne her family lost, she would already be there. Instead, she's wasted 5 books and counting (okay, so she wasn't in book 4, but still) playing great emancipator of some other country, forcing her westerosi values on other cultures, and toppling governments with no replacement proposed, then wondering why things turn to crap when she leaves.
Come to think of it, I think she'd be a pretty horrible queen. O.O
So yeah, Stannis! Granted, this is George R.R. Martin, and in his universe the assholes tend to be the only ones who get ahead, so I'm sure in the end it'll be littlefinger on the throne with Ramsay Bolton as his hand.