I would think the 7600GT as it is small, quiet, and the fan in turn doesn't spin up high or needs to as the max loud temps are like 60C anyway. Can be had for $190-220.
You can get a b*tchin' watercooling system for $250. Run with some silent 120mm fans on the radiator, and you will have silent cooling on both your video card and cpu!
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7900GT/7800GT. And if it's too loud, spend like $30 on a aftermarket cooler. Some of the bigger companies even let you keep your warentee after replacing the cooler now. I think.
Well I should have put in there that I mostly buy used hardware. That hsould put quite a number of x1800 and 7800 products into my price range. Great suggestions though. I don't think I'd be happy with 7600GT type performance.
Watercooling is interesting but I can't even find a place that has a selection of the stuff. I do know that eVGA doesn't make that violate your warranty but for the other manufacturers it doesn't seem so. Basically I made this thread to try to avoid that whole situation.