Thanks for the link! I had actually already had a look at Monit - it falls pretty squarly into the "overkill" category for my needs. ;-)

It's also written by guys who seem to have very different ideas on how to monitor from me; most of their features are things I have no interest in whatsoever.

They're mostly focused on "local" monitoring, while I really see very little point in anything but remote monitors; making a machine monitor itself just strikes me as silly. If the machine is broken or offline, how can you expect it to let you know? Odds are any serious problem will interfere with the monitoring/alerting system itself.