Currently im using EVGA GeForce GTX 580 1536MB 384-bit
www.newegg.com/Product/Product.aspx?Item=N82E16814130595
Its really good and i was playing the beta on high
Really amazing graphics really recommended
People say this card is much better and runs battlefield on max:
www.newegg.com/Product/Product.aspx?Item=N82E16814130587
Wont buy it though ill stay with mine for a while
Btw
They said the beta graphics were lower then when the game will once it comes out
so if you were playing the beta on high for example then once the game comes out it will be like medium on it
Read about it on the forum dont have the link though
Edit:
If you want to but a graphic card make sure you have enough ram to run Battlefield 3 or any other game on the quality you want.
Really stupid to buy a card to play Battlefield 3 on maximum settings when you will crash every 5 minutes because you run out of memory(ram, same shit :3)