Damn man, sorry to hear about all the trouble you've been having with your Power Mac, then to receive a scratched and dented refurb PB on top of that. Wow. At least you got the new PB in and it's fine. Definitely glad to hear that.
Your Power Mac is definitely a lemon and they should replace it for you. Hopefully you'll be able to get a new Dual 2.7, so that you'll be able to actually work without worrying about kernel panics and other problems.
Ya know, I've used Macs for well over a year and out of all the Macs I've had in that time, (eMac, Power Mac G4, iBook G3, PowerBook G3, PowerBook G4 Titanium) I never once had a single kernel panic or any significant problem. The PowerBook had a problem where it would just go to sleep when you moved it around, but I knew about that problem before I got it.
Good luck with the new PowerBook, man!