Superman, and his abilities, are of course very well known to the public at large. What abilities do you believe would be his most identifiable, the thing people think of when they think of Superman?
The two that come to mind of course are flying and superstrength. Everyone wants to fly, and pretty much everyone associates this ability with Superman, even its highly common to superheroes. Same with super strength.
Conversely what would be a ability that only a comic book fan would know?
Super ventroliquism comes to mind, as does the super kiss although I believe that was a one off ability.