I never understood the stigma of the word "cunt". To me it's no different than any other swear word, but to others, it is offensive as "nigger". The common response is that it's "derogatory towards women", but so is "bitch", and that word isn't considered nearly as offensive.
Also, men are called cunts too. In fact, cunt.com redirects to a Wikipedia article on a male British politician.
I will call anyone who truly pisses me off and enters my personal hall of shame a cunt, regardless of gender. Deal with it.