The 4670 is a highly underrated card. I just did an install for my brother in law this weekend, and the 4670 512mb GDDR3 was chosen for its price and lower power consumption. I was very impressed how it ran on his computer (Athlon 4200+ 2gb DDR2667 Vista Home Premium). It ran so cool, I was able to OC it to the max CCC settings (800/980) and it passed 4 hours of furmark without breaking 60c, and idles at barely above room temps, with the fan set at 30%.
For $85CAD, I was very impressed. He runs at 1680x1050, plays WoW, Fallout 3, Oblivion, Gothic3 as well as some other RPGs, and it was playing those games VERY smoothly at decent detail levels.