Definitely Mac Taylor for me, no contest. Compassionate and caring, yet tough as nails when he has to be - but always fair, IMO. He doesn't pick favorites, everyone is on the same level with Mac, no matter who they are. I like Horatio too, he definitely has a ton of heart and compassion, and he would literally take a bullet for any member of his team, IMO. I don't like Grissom as a Supervisor at all, I don't know if I could ever trust or respect a boss who sleeps with a direct subordinate, it's kind of a "Do as I Say, not as I Do" thing... he's a good CSI though, just a terrible supervisor IMO.