I've had the opportunity to be a beta tester for a new company that is writing some great network management software:
Packet TrapThe software focuses around SNMP monitoring from SNP enabled devices and getting pc and server stats via WMI.
For example: you can monitor cpu, temp, free hdd space, and memory usage on a server or pc, look at your traffic stats if your home router has SNMP capabilities, check the status of your exchannge or sql server, as well as a lot of other custom gadgets.
Right now this is an actual app that you have to launch, but the next release will be run as a service and be web based.
The free trial last 30 days but they have a lot of free tools that don't expire.
I just thought I'd post this in case some of you might be interested in playing with it.