If your buying a new gpu, then go with the 7800. I doubt that ATI will have its video cards out to the masses like nvida did, esp since they are rumored to have problems getting all 36 pipelines in their video cards to work.
This is rediculous. I was so excited for the new cards... but *pop*
...see that? It just deflated all hopes that I had for the new line of cards. I'll have to wait until ATI releases their stuff to see how the 7800GTX stacks up. I'm going to make a prediction though... ATI kicks NVIDIA's ass with the new line of cards.