dude get HD 5850 jeezz. Why are some of you still buying nvidia card omg! FAIL FAIL AND FAAAAAAIL!
thats like asking why do you go to this store when there another store that has the same items for cheaper price.
It's personal preference.
You honestly shouldn't be shocked that people are still buying nvidia cards. There many people that dont keep up with todays tech news (like us) but are system builders. They probably remember that Nvidia is (to us "was") the performance champ and will stick to that.