I'm afraid there's a grain of truth in this stereotype. Ask any waiter who works in a Chinese restaurant or Jewish country club. I wouldn't have believed it until I started delivering pizza in a very wealthy town and noticed how small the tips were on every house with a mezuzah.

Always tipping generously and urging our fellow Jews to do the same will do a lot more to alleviate this stereotype then making a stink whenever there's a tasteless joke about it in the newspaper (at best, that replaces the 'cheap jew' with the 'touchy jew' - not exactly a huge victory).