Our start-up (i-conserve.com) looked around on the web, saw that most were partial copies of each other (as in, whole paragraphs verbatim), and decided to write our own, based on 4 or 5 we liked. We really liked the bare-bones approach most YC companies have, and tried to follow that philosophy when writing such legal documents.

Then we talked about to a local long-time entrepreneur, who said that is exactly what his lawyer did, and charged him thousands for it; in fact, it didn't turn out that great. So, save some money and write them yourself.