Any well known pro is a safe "best" especially any past winner or final table players from the
wsop main event.
Personally, my two favorite (and I believe best live players) are Daniel Negreaunu and Phil Hellmuth. Both of these characters are usually seen as hate or love because of their personalities.
I like Negreaunu because I like what he has done to promote the game of poker. Some players complain how he talks too much or jokes or whatever, but no one can deny that he makes poker fun to watch. Bonus when he seems to know everyone's hole cards
I like Hellmuth because he is such a good poker player. I know he gets a bad wrap sometimes for his reaction to bad beats, but he really doesn't tilt the same way; he might swear or stand up, but the act is over by the next hand. We can all learn from him about how to not let one hand impact the next unnecessarily. Plus, Hellmuth is usually right. I used to look at him strangely when I'd see the guy throw a tantrum, but the more I've learned about poker: the more I realized he was right (and sometimes that meant acknowledging that I was wrong). For what it is worth, I've been seeing more of Hellmuth's personality in my own game - for better or worse (minus the swearing and personality he has on bad beats, but then again I don't play his high stakes level either).