As far as the player as a person: Barry Greenstein. This guy is so generous (gives a lot to charity) and successful. A great role model. Ok, I am slightly biased since the couple of times I've e-mailed him I've actually gotten a reply within 24 hours. Check out his website!
As far a the player and his playing style: Tough one, but I have to give the edge to Daniel Negreanu. Watching him play on High Stakes Poker, I have a lot of respect for his game.
As far as the player for entertainment value: I'll have to go with Phil Laak. The guy is a complete schizo goofball and I love him for it.
I'm watching Poker After Dark right now... and Phil Ivey is tearing up the field. He puts Sam Farha all-in with only a pair of Aces knowing that Sam also has a pair of aces but a lower kicker what a gutsy bet... this guy is fearless and I love his playing style. I've almost never seen him make a bad decision.
I watched that Poker After Dark, and was suprised I could name all the players. Phil Ivy is no fun at a table. Quiet, moody, sucessful. Deadly.
Hellmouth was not obnoxious and almost a pleasure to watch. There are rumors he is like that most of the time.
Matisow at a table is fun, as would be Daniel.
I think I like watching Jennifer Tilly most.
My guess is that at that level, all the players are nearly equivalent, and it becomes style that wins or loses.