Hitmonchan

Its arm-twisting punches can pulverize many foes, even concrete.  After about 3 minutes of fighting, it will take a break.  Sometimes, it delivers punches so fast at opponents, it might not seem like it's doing anything at all.  It seems to have the possession of a spirit that a pro boxer had; the boxer would want to be a world champion.  It can punch through a concrete wall like a drill could.
What's up with that purple outfit?  Is it even natural for a wild thing to have clothes on?  This is Hitmonchan, the one out of the "Hitmon" category that seems to be based off of a boxer, and is therefore focused on punching- (just check out its movepool).  It has a high Attack stat; no big surprise there.  It has high Sp. Defense as well, making it useful for surviving a few super-effective Special attacks.  It has okay Defense and Speed stats, making it somewhat more robust and useful than Hitmonlee.  It has low Sp. Attack stats, but who needs it anyway?  This Pokemon has a boatload of Physical moves.
Hitmonchan is focused on punching.  Comet Punch, Ice Punch, Fire Punch, Thunder Punch, Sky Uppercut, Mega Punch, Focus Punch, Mach Punch, Bullet Punch- several punching moves.  Most of these moves are always useful, and that's what makes Hitmonchan look a little better than Hitmonlee.  Hitmonchan has several good attacks in its movepool, and that's what makes it handy.
Hitmonchan has an ability called Iron Fist.  The power of punching moves, like the moves listed in the second sentence in the paragraph above, and some more, are a little bit more powerful.  It's a great ability on Hitmonchan.  Hitmonchan also has the ability Keen Eye.  Hitmonchan can't have its accuracy lowered.  It's not a bad ability but if I were you, I'd stick with Iron Fist.
So Hitmonchan isn't too bad of a Pokemon at all.  It would at least be a great Pokemon to try out if you aren't 100% sure on what Pokemon you should use.