Dual Core or Dual Processor

So I'm in the market for a Power Mac Dual G5, either the new ones that came out or the Revision B ones with 8GB max RAM (The good revision). I was wondering if I should get the new Dual Core 2ghz with educational discount for 1799 or should I get a refurbed Dual CPU 2ghz at the Apple Store for 1499. I know the differences between the two, PCI express, 16gb max RAM, etc. But what would be the better deal? 1500 is kind of my budget, but if I can get a lot better computer for a few hundred more, I might just be able to swing it for Christmas. I don't really want to wait for MWSF so please don't say to wait until then. I do a lot of audio work, web design, photo and video editing, etc. But from what I've read, the performance difference isn't all that different between the two computers. Thanks for the help.

if the perfomance isnt that great then why not save a load of cash then and spend it on something else