For TODAY'S games, either camp will do/run them with high settings, good IQ and decent frames with relative ease. The NV8800GT/GTS cards are still fantastic bang for buck. They aren't as fast (in raw power) as the latest from Nvidia (GTX260/280) or ATI (4850/4870)but are still a great solution for most people in the single-card setups and even good solutions for those wanting to run SLI.
I have a single NV8800GTS 512 right now and have great IQ. I run 8xAA, 16xAF globally (though AF has little benefit for IL2) and rarely, if ever, go below 50 FPS and typically stay in the 70's at 1680x1050.
The true question should be: Which platform will run the next-gen games/sims with the best frames and the best IQ? There's no way to know that right now. Maddox has used NV cards for years in most of their pc's (according to interviews and readme files of the past) and likely will continue to do so (speculation) as long as NV stays on the front side of the performance curve.
I like the status of ATI these days and the release of the 4870 card is showing to be a great card with fantastic performance to price point.
I'm still leaning towards a GTX280 myself, but will wait until the price comes down. Perhaps one of the better cards right now is the GTX260 which is comparable in price to the ATI card with similar performance in some areas and even better in others.
Here are a few benchmark graphs from assorted (trusted) sites:
and some links:
http://translate.google.fi/translate...hl=en&ie=UTF-8
http://www.overclockersclub.com/revi...r_hd4850/7.htm