Finally got around to fixing up my e1505.
I picked up a Core2Duo T7200 on the Bay,
two 2G PC2 SODIMMs,
and a tube of thermal compound.
Maybe $60 all told.
While I'm still running Vista, everything is sooooooo much better. My wife's Facebook games are playing smoothly where before they were laggy and froze a lot. I haven't tried any of my games yet, but I suspect they'll do pretty well now. The graphics card is still the X1400 it came with, but I don't really plan on doing anything horrifically graphics-intensive. If I can find a good deal on a key, I'd like to install a newer OS (7 or 8)... or maybe even Hackbook it with Snow Leopard. I've had this thing for years, and never cared for the performance with Vista, but it's a whole new machine now.
It has the latest BIOS update, A17.