As someone who has owned both Zs (350Z and 370Z) as well as a C6 Corvette these comparison threads make me laugh.
Bottom line it's like comparing apples and oranges. Both cars are capable cars and great perfomrance bargains, but in different price ranges and with different target markets.
All things considered (including price) I prefer the Z. That doesn't mean I didn't like Corvette, just that overall I would rather have a Z. However, performance wise the Corvette is the king of the hill in almost every category. It really depends on what you want.
What I want is a Z with an LS3 motor.