You'll be fine with the Athlon 64 venice though. It would be so nice to match the 7800GTX card with a more powerful processor.
If I had to choose between CPU and memory, I would choose CPU simply because they cost more. DDR memory may come down in price for the anticipated DDR2 coming out for AMD in the future.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?