I like the original Scarlet Witch (with the hex bolts, pre-chaos magic/reality manipulation/no more mutants/life-force retcons), but she's not an X-Man, and no longer even a mutant, so I won't vote for her.
Never really been a fan of Rogue, so I'm not voting for her, either.
Northstar and Quicksilver? I like both of those snarky silver-haired speedsters, that could be a hard choice!