When both of my lowly components are balls to the walls for an hour, about 40C. And that's with my TX3's fan hovering around 1000 RPM. I love slower and more effiecient things for this. Too bad the Athlon II X3 455 I plan on getting will kill that idea.
EDIT: And for my netbook sitting here on LTT at 1.68GHz...
Case: 56C
Processor: 54C
HDD: 36C
I'm not using it on my LEGO laptop cooler, so it runs a lot hotter when it's not on it.