Still doesn't bode well for his hopes at a title.
Best case scenario for Mclaren: Button overtakes the first four as they pit and builds up enough of a lead to keep clear of them till he does his single pitstop... Vettel has to stay ahead of Webber and Alonso or Kubica leapfrogs him. Hamilton ends up fifth or sixth, depending on his luck. He's faster than Kubica or Alonso... but he'll have a hell of a time overtaking them both.
Best case scenario for RBR: Fault-free race... enough pace over the first stint to stay out ahead of Button after the pits. No funny stuff from the boys.
Best case scenario for Ferrari: possibly third ahead of Kubica. The Ferrari doesn't quite have the pace to take the RBRs in a straight fight. If the RBRs tangle, Fernando's chances of taking the championship lead is good.