I dunno ... the specs look pretty good ... at least on paper (ATI $uck$) ... only not too much has changed since the G4 (yeah the one before the new G5). Let's put it this way, the components inside have improved, but the overall layout is the same as the G4. (Nothing "revolutionary"). Of course it is better than the G4, but only by about say 25% ... rough estimate
Would I buy it ? No
Why ? Because I don't like Macs, besides the next computer I buy will be one I build ... and it will eat the G5 for breakfast !!! MUHAHAHAHHAAAA

(I don't mean to crush your hopes for the G5, I'm sure it's better than most on the market ... I'm just saying that one can build something better from scratch, and cheaper too) I mean $2000 - $3000 for it is a bit much don't you think ?