Our tech guy here took my laptop apart into tiny pieces and reassembled into a whole beast again. There are a couple of ugly cracks, but otherwise it appears to be roaring once more. This probably means the end of the Powerbook experience, though it was fun I liked the applications on OS X; in general the freeware stuff tended to be much higher-quality than what you get on Windows, which suffers from (a) too much legacy (b) too much signal-to-noise (c) lower-quality developer tools.
However, I missed the zippiness of my Dell laptop. The turnaround time on some of my code edits was like watching grass grow. Extrapolating from my history file I spent 32 minutes today waiting for my code to load on the 500Mhz (almost 30 seconds per load). If I did the same task on my 1Ghz laptop it would have only spent 6-7 minutes (we clocked a 1.5 Ghz Powerbook at 11.5 minutes).
My conclusion: it would be nice to have a Mac around the house for non-coding tasks and to run Mac-only apps, but at work I can't live without my PC.