If you will save money and time in the next months go for it. I bought a new PowerBook G4 in November, it works really well, it does everything I need it to do for now. As far as I know there is no other hardware coming around the corner that as the potential of replacing PCIe slots and every video cards company is coming out with new PCIe products.
You can only have the best computer for one day and thats if shipping is not delayed. Think about it.
I don’t think Walter is having problems doing HD on a dual 2.0, so the only question is do you need it or not.