Best PCI-E for under $200?

im trying to build a new computer but cant decide which video card to buy… and i dont want to spend a whole lot either… under $200 if possible…can anyone suggest anything worth the money?? ive been looking at the nvidia 6600/6800s or the ati x700/800s… are there big differences between 2 brands that make type of card…what are the important specs i should be looking at? core clock, memory clock, pipelines, ramdac?? not really sure what all these are… i was looking at getting this one… http://www.newegg.com/Product/Product.asp?Item=N82E16814150098 but wasnt sure… i want a decent card thats gonna let me play HL2 and BF2 without any huge loss of quality… thanks for the help in advance…