This leads me to my first mistake. I cracked the case open, remove the crumbly mess from the old thermal pads and installed the new stuff. What I didn't do was properly clean the chips and once I put everything back together, temperatures were only marginally better. I was still getting temps in the nineties during stress tests, so I guess I did a botched job and had to redo it properly. Thirty minutes ago I did just that; I polished the CPU and GPU chips until they actually shined and thoroughly cleaned the heat sink on the bottom panel for good measure. Now a 10 minute CPU stress test brings the temperature in the eighties and idles in low fifties, upper forties. What I don't see anymore are spikes where it shoots up in high nineties by merely launching an application. It's a lot more even-handed.
Moral of the story is: do a clean job, berk.
Blair 