Video card depends on what you intend to do. Like, what games? If mostly older, you could save money on the card.
In general though I recommend the most expensive Radeon 5xxx card you can afford with the 5670 as a minimum.
Also, just make sure you are not playing FSX. That is one of the rare games that will utilize the CPU more than the GPU.
I have an Athlon IIx4 at 3.25GHz. Currently most games use no more than 3 CPU cores. This could of course change in the future. I say though, buy for the now. Because really, saving $200 on the CPU now, in 2 years you could get something significantly better for that extra money.
I think, for example, An Athlon IIx3 3.0GHz system with 4GB DDR2 or DDR3 memory and a radeon 5770 would make for a great system.