Personally, I prefer my superheroes not to have superpowers in the traditional sense. The martial arts based superheroes, like Batman (although I'm pretty sure most of Batman's appeal stems from him beating enemies a good few orders of magnitude more awesome than he is) are a lot more fun because there's a sense of vulnerability there. At the end of the day, they're still human, a lot more human that a man who can fly and break cars in half and stuff.
My favourites, though, are the smart people. Call it wish fulfillment, but I love it when protagonist superheroes think their way around problems rather than just punching it. Maybe that's why I like the villains more than the heroes most of the time; they're the actual smart ones and the heroes are an inherently destructive rather than creative force.
And I bloody hate magic superheroes. They can all piss right off.