Don't forget the environment!
Add environmental monitoring to the list. Temperature, humidity and leak detection are a must IMHO.
It all goes a bit smelly when the CRAC stops working, either because of a fault or because of a power outage and the CRAC doesn't start up again after power is restored.
Add leak rope on top of racks if you've not been able to divert overhead wet services and/or wet contact sensor under the floor tiles if you've got a void under your expensive equipment and priceless data.
Some metered PDUs (dare I say it, APC) have built in environmental monitoring if you're very tight on space or want an "all-in-one" solution.
Biting the hand that feeds IT
