the x1950xtx. it supports avivo video converter which is a plus, has GDDR4 memory which is also a plus, and it'll do both HDR and FSAA for you, which to this date no nvidia gpu supports... plus ATI is working on havok FX which is a driver used to plow through physics with a graphics card. turns out its very effective and its something you'll need for future games... theres no turning down the physics in games like theres a such thing as turning down graphics... especially in multiplayer mode. you cant have two different computers fighting over whether or not an object exists in the 3d environment lol
im not sure if you need your primary graphics card to be an ATI card to use this technology though lol... good for an upgrade and some amazing gaming lol