-He has a great sense of humor
-Amazing accent
-He's sensitive
-He's brave
-He's adorable
-He's confident (except for when some jerk is racist about his mutation D:<)
-He's loyal
-He's handsome
-He stands up for what he believes in
-He's compassionate
-he has a good heart
-He's an amazing fencer (fencing ftw)
I like Rogue and Storm, their powers are great!!! (especially the flying) And they also just look nice. Also like Wolverine, for his jokes are really funny! This is only based on X-men The Animated Series, though.
Cable because he is a total badass even without powers and is the most powerful telepath/telekinetic on the planet with his powers. He also has an interesting back story and is willing to put the cause before himself. And he doesn't constantly whine about the stuff he's been through even though he would be perfectly justified in doing so.