I would say rock, but I'm definitely using one of the new fossil pokemon, so not that one.
Probably grass, since I don't think I'll be picking Chespin as my starter. I may change my mind if he gets a badass final form though. --- The official Quick Man of every board. http://i.imgur.com/kgk3sk0.gif?1 I'm still faster than Sonic.
My initial playthrough on X will not have any Fairy Types because my initial playthrough on Y will be a Fairy Monotype Playthrough. --- Xerneas, The DNAntler Pokemon Currently Awaiting...SSBU, SSB3DS, Pokemon X, Pokemon Y and Watch Dogs.
Rock or bug. I've never been a fan of any of them and the new rock and bug types don't appeal to me either. I voted rock though because rock is my overall least favorite type and at least a few bug types are neat.