The cards I listed were just examples of DX11 cards that fit his budget. Also, as you may know, computers get old fast. That is why it makes sense to purchase a card that is DX11, Nvidia or ATI, who cares. The only reason I mention ATI is that there's is out already and have had time to sort out issues, glitches, etc.
A game comes out in 6months that you really want but is dx11, the card you bought 6 months ago is not, now you hate yourself. Get the idea?
I bought my CPU case HAF 922 because I know that I will need room for the 5970 I want as it's a long card, get the idea?
Preparing for the future is always best. ;D