I love the custom poller feature in NPM. You can monitor anything. However I think SolarWinds leans on this feature too much. I honestly believe that at this point any device that is used widely should have its SNMP info canned in SolarWinds. This is a selfish motivation of course as it would make things so much easier if say it would auto pickup things like CPU, MEM, NIC, DRIVES etc for things like AIX, Bluecoat devices, large UPS's, other widely used appliances etc etc etc.
I do not expect for Solarwinds to just load it up with just anything but it would seem it would behoove the company to load up anything that thousands of customers would use.