An interesting question...
Some of you may laugh at this. I certainly had to have a chuckle, but the question was serious, so I tried to give it a serious answer:
Does the rotation of the earth affect blade performance of counter-clockwise turning rotor-systems vs. clockwise turning rotor-systems, depending on which hemisphere you are in? ie; does a counter-clockwise turning rotor get extra help from the earths gyroscopic forces in the northern hemisphere?
I had to answer yes, probably to an almost immeasurable degree. But then I started to wonder and my brain got fried. Anyone smarter than me care to take a stab at this?