IGN Comics is having a poll on Superman's Best Attribute. This survey is being conducted by Hilary Goldstein, who absolutely does not get and/or hates Superman...so if you'd like, you can vote in the poll and let her know what Superman fans think. So far, "sense of right and wrong" is winning, but only with a plurality.
http://comics.ign.com/articles/683/683071p1.html