Quote - Something that also helps - ditch Vista and install Windows XP 64 bit (getting hard to come by, alas).
Caveat - check hardware support first. Mainboard should be no problem printers can be troublesome (for example, HP has removed the XP 64 bit drivers for the HP PSC2100 series all-in-ones from their site), scanners are definitely trouble.
So are ATI graphics cards. nVidia has good XP 64 bit support (and good Linux support), ATI has none to speak of.

@thartwick: do pickup Poser 7 for that quad! You'll find that rendering will be at least twice as fast as on the G5. Poser 6 has a single threaded renderer, so it will only use 1 of the 4 cores, while Poser 7 can calculate at least some parts of the render using 4 threads.
Don't expect quadruple speed - Firefly isn't that smart or efficient. But you can expect about double the render speed (YMMV - a LOT depends on the scene contents and layout).

Thanks. I'll have to save a few pennies and pick it up!!!