On the subject of AMD versus Nvidia, I had always liked AMD/ATI cards because they were typically lower in power consumption and heat output on their mid range cards, and that was a big deal for me since my case was (and still is) poor at circulating air. I think that's kind of changed recently, and now Nvidia has the edge. Or, at least, the 650Ti I got has the edge compared to the AMD counterpart in it's price range (it's also not as powerful, though).
As far as drivers go, I never really had any big issues with AMD drivers. There was a point where I'd have problems because I didn't have the right (early) .net Framework installed, but I think that was more of an issue with Windows XP. I do like that Nvidia's drivers much lighter-weight, and that translates into my computer coming to a complete boot-up about 20 seconds faster. Also, the in-built custom resolution tool is very handy, and makes doing supersampling on Nvidia much easier.
