While insults with lots of profanity have their place and time, I also like the subtle ones and the ones that are said deadpan. Any Groucho Marx movie/show will have tons of them.
"I think you'll go very far. Why don't you start now?"
"I'll never forget a face, but in your case, I'll make an exception."
EDIT: Mae West and W. C. Fields were good at them too.
I'm an old movie buff, what can I say?