I spent a lovely weekend morning setting up monitoring on servers - yes, what fun :-)
I like all my servers to run
logcheck means watching your email every hour, and adding in yet more ignore rules for things your server thinks it's perfectly OK to spit out.
smartmontools means waiting to see which attributes it's going to complain about, making sure it's set up to mail you about bad sectors, and getting this all in inside the 128-character line-length limit.
And lm-sensors, well that takes a lot of tweaking, to get all the alarms to stop ringing, labelling the right temperatures, and ignoring the disconnected pins.
Ugh, it's painful work, but it helps in the long-run...