I've switched out all my own monitoring of my servers to Hetrix Tools, and I've been really impressed with the features, reporting, alerting, and monitoring. I've got 20 server monitors, plus their free black list monitors for IP addresses.
Free Uptime Monitoring - HetrixTools
One of my first VPS that I set up with them. No longer needed, so I'm going to be destroying it:
14:21:42 up 608 days, 18:57, 2 users, load average: 0.04, 0.03, 0.05
Can't argue with that sort of stability for $5 a month!