Who would you say the most underrated X-men in the whole of X-men history are?

My brain just completely blanked out on the whole history of X-men, so I'll have to come back after I"ve run this one through my head for a bit, but after a moment the first one to pop into my head was Bobby Drake. That poor kid can't catch a damn break. He's either a crappy background character, lost in the plot, or he's being screwed over in the foreground.