The 4870's do not come w/ 1G memory as standard, but 512MB. However, there are some 1GB versions being released. These cards are more expensive, and from what Tech said in his original post, they might be out of his price range.
I've never experienced any major driver issues w/ either NVidia or ATI products. Guess I've been the lucky one. I've owned several of each over the years. I must say the ATI 9800pro and the x850xt were probably the best I've ever owned. That is, until I bought the EVGA 9800GTX+ 2 months ago. I do like the CCC of ATI better than NVidia's control panel.
And now I'm waiting on my EVGA GTX260 216core card. I should have it tomorrow.....should be a beast!!
With 896MB of memory, I still say the GTX260 is hard to beat on the price\performance front.