All I can say is that the iMac I have certainly gets a bit of a pounding, below is a screen grab from the Menubar showing some key stats of the system.
Although, the machine was certainly doing some heavy processing. Ripping a DVD image, running VMware Fusion, Adium, FireFox and using HandBrake to convert some DVD vob files into another format.
Not to mention it was dialed out to the internet via Three X-Series plan on my wife’s Three mobile, then sharing it out via wireless to her MacBook nearby.
It’s great when things just work.