If you need to monitor M$ Windows servers #NSClient++ is a nice tool. Today I had to change some service checks and tried the release candidate from v0.4.2. It is quite different, but it is absolutely worth to dig into the new configuration and possibilities. The new filters and all these things are so powerful and amazing.

CheckSystem — NSClient++ 0.4.2 documentation

Various system related checks, such as CPU load, process state, service state memory usage and PDH counters. A list of all avalible queries (check commands) A list of all short hand aliases for queries (check commands) Commands (executable): TODO: Add command list A quick reference for all avalible queries (check commands) in the CheckSystem module...

Just not got  [/includes] working yet to better structure all the checks.