I'm getting ready to upgrade my single-pc setup, and I'd like to see where the best place is to put my $$. A typical project runs a few dozen tracks, running EWQLSO Gold, GPO, SAM brass, etc. through Kontakt 2, as well as various & sundry fx or synths inside Sonar 4.

Here's the current hardware:
Asus A7N8X (nforce 2)
Athlon XP2400
2.5 gigs of Kingston PC2700
Sample drive is a Hitachi Deskstar SATA drive
M-Audio Delta 66 audio card

I'd like to get better poly - I usually top out around 150-160 when all the guns are blazing. If you are getting more voices in K2, what's your system? I'd like to upgrade the worst bottleneck, and I'm hoping I can re-use/keep all that RAM.