Derek runs into issues with sendmail. This is one of the reasons I switched away from sendmail. Sendmail is powerful, it can do all kinds of things when it comes with dealing to email. The issue is, most people don't need this kind of power. For most people, something like postfix works just fine. I switched about two years ago and I love it. It's insanely easy to configure and just plain works (and I just figured out how to do pop before smtp authentication with it).