Aw, come on Gregg, there are currently only two "critical security problems" listed on the sendmail.org home page. That's actually pretty good for them
I would second ignoring Sendmail (indeed - do an rpm -e on the thing). However I'm a fan of
Postfix myself. Postfix is included with RH9 and Fedora. You don't state what distro you're using but it is easy to compile too.
Note that I have not personally used QMail so I don't have an opinion on it.
[ October 26, 2004: Message edited by: Scott Dunbar ]