Yes that Video card will work on your motherboard and with your power supply.
The choice between video card manufactures is a very debated subject, usually there is not a huge difference at given price points. A 200 dollar Nvidia card will offer very close performance to a 200 dollar Ati Card, or Vice Versa, etc. That being said Nvidia has PhysX, I don't know what Ati has. Seriously though, use http://www.motherboards.org
or others, reviews to help your decision on Ati vs Nvidia.
Just because your not paranoid dosen't mean they're not after you.
If you are reading this thank a teacher, since it's in English thank a soldier.