I'm very suspicious of Alberto Contador. For the last two weeks of the Vuelta he has been struggling to keep pace with the other leaders of the race. Then all of a sudden, today he takes off from out of nowhere and puts enormous amounts of time between himself and his nearest rivals. This is classic doping behaviour. It might take a year or two to become proven, but since he's only just emerging from a previous ban for doping, my money is on a longer term revelation.