It's Hitmonchan, for me- I just like that he learns the elemental punches on his own, it helps him cover a lot of bases and that's something I like. I've never actively used ANY of the Hitmons in a team, though.. While I like that Hitmonlee's generally better for attacking, I find that whenever I'm facing one, he always relies a lot on Hi Jump Kick, which.. I don't really like. As for Hitmontop, I don't really like it much at all, it's always seemed a little but unnecessary to me.