Mitch Berg has a good list of reasons why Arnold Schwarzenegger is not another Jesse Ventura. Certainly Schwarzenegger isn’t running on a lark, and is definately more personable and likely much smarter.
I’m still adopting a wait-and-see attitude about Arnold. However, if he surrounds himself with good people, he could very well be exactly what California needs. However, if his advisors are more suited to Hollywood than Sacramento he may run into some problems.
Then again, just about anything would be better than Gray Davis at this point.