Mike Carey, as he previously announced, is ending his tenure as writer of X-Men: Legacy with issue #260. His run began focusing on a rehabilitating Professor X, exploring the unaddressed tensions and minutae of continuity, the emergence of Rogue as a woman in control of her powers and a veteran capable of leading and teaching, and the constant struggle for identity among all the X-Men, both young and old.
It will be a massive shame to see him go. I believe him to be one of the best X-writers we've had in a long time, and I can only hope that he'll return eventually. One can sense that he cares about the characters just as much as we do, and that he gets just as excited while writing a cool Magneto fight scene as we get while reading it. Go to Comic Book Resources for a nice little interview about his upcoming exit, current story arc plans, and his feelings on working in the Marvel Universe in general.