I found an interesting website through Eric Zorn's blog this morning: Live Science: Most Popular Myths in Science
Of the 20 "myths" listed I was aware that many of them were myths before looking at the site, but that may not be true for everyone. I'd also caution you that not all the "myths" are myths, so do click and read them.
The one I wanted to highlight is Coroner-related and I have gotten questions regarding the subject and tried to set the record straight. Is it true that your hair and fingernails (and toenails) continue to grow after you are dead? The answer is no. That growth would require the continuation of circulation and metabolism that cease at death.
Sometimes these myths take on a life of there own.