Keep an eye on your system's vitals with Yet Another Process Monitor
Apart from showing task manager-esque information about running processes, YAPM also provides details about Windows services and your network activity. The system information panel provides realtime monitoring of processor, memory, and disk activity. Service startup types can be managed, processor affinities specified, and there's a grayed-out option for limiting CPU usage that will likely be active in a future version.
Don't recognize a specific process (say, for example igfxpers.exe)? Highlight it and click the internet search button to be taken directly to Google's results for clarification. You can also put YAPM's Kung Fu to use monitoring remote machines on your network.
In all honesty, there's so much built in to YAPM that you really need to download it and give it a try - assuming you want a better system monitor.