Well I am a friggin genius for X-Men and pretty much every otehr comic book out there. And my favorite person in X-Men is Nathan Grey. He is the son of Jean and Scott.
And his powers a telekensis and Telepathy. His telepathy is so so, but his Telekinsis is uber crazy. It is so powerful that he can literally rearrange someone's molecules to make them melt. Needles to say he is the most powerful X-men so far. Hell I think he is one of the most powerful person in Marvel period.