I hate being in this little (or big, however you wanna look at it) predicament.
Ya know, come to think of it, the same thing happened to me last time. Bought my MSI K8N Neo2 Platinum (nForce3 Ultra chipset) mobo, GeForce 6800 GT AGP videocard, and AMD64 3200+... I was happy being at (basically) the king of the hill for several months... Then PCI-E hit... And nForce4 hit... And I was sad.
At least it wouldn't be as bad, really at all, this time. I'd be able to save ALL of my computer's components. Just swap the mobo out and call it good. Add new videocard and uber processor, and I've got myself an UPGRAYEDD.
Can ya tell I'm trying to talk myself into this?
If you really can't wait, just get an Asus X38 with ddr2 and you're set.