Bah. All superman needs to do is stay out of the sun for long enough, and you can kill him.
Someone quick! Introduce Clark Kent to WoW! He won't get sun for months. Then, you just waltz into his room and blow his nutsack off with a sawn-off.
I'd like to see Hulk get so pissed that he exits his physical body.
Instead of being powered by psychic energy or whatever, he's powered by ARRRGH FUCK YOU