This one will either get you in trouble or have them / or their buddies laughing so hard that they buy you a beer:

Jerk: "Hey, Nice Skirt"
You: "How are you going to explain to your buddies that you got your @$$ kicked by a guy in a skirt?"

2nd retort:

Jerk: "Hey, Nice Skirt"
You: "Some men just need more room than others."

That being said, I usually ignore rude drunks and act like I don't hear them. Usually their friends yank them back to the bar after the first or second "announcement" before they can really do any damage.