I hope everyone who compares 7D vs 5D2 noise performance realises that, in order to use the same ISO setting on the larger formats, they will get either reduced DOF or longer exposure times for a given framing and perspective. For low light photography, it is a given that you don't want longer exposures, and if you don't want the DOF any shallower than what you get with the smaller format, there is no noise advantage from the larger format.