Personally, I always wanted one that says "poetic," but nobody ever understands. (Poetic LICENSE, get it?)

On my way into work today I saw one that said O JST LAF (oh, just laugh) and I thought that was both good advice and an omen. So today I am determined to do just that and not let anything get to me!

My other favorite I've ever seen was on a white Volkswagen Rabbit. It said HARVEY. (I love that movie!)

What are some good ones you've run across?