Clowns are quite creepy. Superman just might be the most awesome superhero ever. A clown costumed Superman would no doubt produce and awesome amount of creepiness. For the first time I realise that tights weren't such a terrible costume decision on Clark Kent's part.
I get it, clowns are supposed to be cheerful, funny and entertaining, but they just seem to give off an evil impression. You know of many evil clowns; the joker, Stephen King's 'It', Ronald McDonald (though I suppose that is a matter of opinion).
In fact, when I think clowns the only possitive image that comes to mind is of a 'clown' that I saw at a circus a few years ago. He was actually entertaining and quite funny, but the reason I didn't imediately resent the clown was because he didn't dress like one.
He wore a calm and welcoming light blue suit, complete with sparkling blue bow tie, and everyone, including Dr. Who, knows that bow ties are cool. He didn't wear the painted red smile or the gloomy painted eyes. There was no mess of wild brightly coloured hair, and he had no red nose. Without The polka-dotted baggy pants or any other rediculous clown get-up, the man was not threatening in any way.
In conclusion, clowns are only non creepy when they don't look like clowns, and Superman is awesome, dispite his weakness to a rare type of stone.