for what i've seen in the last kms of the Andorra stage, Contador seems to be the strongest on the mountains... but in this year's Tour (as usual) mountains stages count to a certain extent (and this sucks, btw... have you seen sunday stage, how such a legendary mountain like Tourmalet was disrespected by organizers plannig the finish line 70km ahead?)...
anyway Contador is pretty fast in time trial stages as well, so i think he will be the winner... moreover, as long as Lance has not gained yellow jersey yet (like it could happen on the team time trial stage), he'll more free to make his own race, without being subject to team rules...