Thanks for the advice about the SSD. I considered getting a SATA card, but a good one (I've been looking at the Sonnet cards) is a bit too pricey. OWC's legacy PATA SSDs look pretty good, I'll give one a go soon.

I tried installing the CHUD tools, but the system preferences page for it doesn't seem to work - none of the settings have any effect, even after restarts. I am running Leopard on a FW800 though, maybe it isn't compatible.