you could put a gtx460 without much bottlneck. what resolution is your monitor? If your into overclocking, that cpu can reach 2.7ghz on stock voltage and cooler and more depending on cpu. with a slight voltage increase you can hit 3ghz+. If it was my computer i would try to aim for 3ghz assuming it does not get too hot. I wouldnt bother with aftermarket cooling unless you can get something really good for cheap. but as a stock system a gtx460 would be as high as i would go. if your running 1920x1080 res, you could aim for a slightly better vid card, especially if you play crysis as its more gpu limited.