Huh, well I'm not sure what was going on, but everything is fine now. I popped the motherboard heatsinks off and replaced the thermal paste just for good measure though. The stuff that was there was pretty dried out.
Anyway, back to playing around with it today. I'm going to try with a discrete graphics card instead of using the onboard graphics and hopefully that will drop my NB temps? Then again, the video card slot goes _right over_ the NB heatsink, so maybe that will just make it worse. =(