This is parts to upgrade my current pc and using the same case. These will be purchased a part at a time.
http://pcpartpicker.com/p/3zo5Z
A GTX770 with outperform the 280x (a wee bit) and its a bit cheaper. I strongly recommend the 770 instead.
Graphics cards for SLI OR Crossfire should be purchased at same time to ensure they are identical, but it's not carved in stone
that good to know