Apparently circumcision makes it look bigger, I don't know this for sure because I don't live in America and the only people who get circumcised here are actually Jewish. And there's few enough Jews here as it is.
I personally am quite happy to be uncircumcised, because I don't feel that I need the confidence boost of a visually larger snake and I'm not a filthy bastard so I'm not about to get a yeast infection.