To start off, I like 20" for gaming. I own a 24" and it is what it is, I just don't prefer such a big monitor for gaming. I've already got most of my parts to build my rig. 600w PSU, Asus EVO 790x MB, Phenom II x4 955, 4GB Ram, and the other stuff. The only thing I've got left is the video card, and I'm torn between the greater, more expensive 6850 and the trusty 5770. I gather that if I were shooting for gaming @ a high resolution as 1920x1200 and whatnot, I'd definitely want to go for the 6850.
My question is on a 20" with a resolution of 1600x900, would the 5770 not suffice with my CPU and such? We are talking $100 after rebate for a 5770 compared to $149 after rebate for a 6850, and since this is a budget build and I splurged a little on the MB&CPU (for good reason of course), saving $50 is a big deal. It's $129 before rebate vs $179, in the case that we aren't relying on a rebate.
Of course, I bought the MB&CPU with the future in mind, CF and all. I need some professional opinions on 5770, and CF if need be in the future, or going ahead and breaking the wallet for 6850, which could also be CF in the future. Keep in mind, we are talking 1600x900 on a 20" here. It's not question if I were on a 24" to spend the extra because it is moreso "needed".