High End Video Card for a Micro ATX Mobo?

I am looking for a good video card for a micro atx mobo. I am looking to play COD 4 and the onboard video card will not meet requirements. Can someone point me in the right direction of a good one that will fit. The mobo supports PCI Express. It is also in a micro atx tower. I was told that all extreme high end graphics cards will not fit. Looking to stay in price max of 250. Help!|||try a 8600gt, it isnt as big as the 8800's and under 200, but get the 512 mb version.