I just made this upgradeable rig yesterday, and it is AMAZING!
i5 4670k @ 4ghz
8gb of ram
ASUS Z87-PRO LGA 1150
Ultra LSP Series V2 650-Watt
Radeon 7770 ghz edition
I am coming from an intel core quad q6700 overclocked to 2.9ghz since a month after it was release. I thought my q6700 needed a new owner so I sold it. I could play bf4 on medium settings with a radeon 7450. The point is you don't need a super expensive gaming pc to play big games. I know this is changing. AMD offers some good budget processors, like the 8350 is a little a head of it's time. What I mean by that is very few games demand huge amount of processing power. Graphics card should be as important as processor. Are you a intel or amd person?
I would recommend a Radeon 7970 for 1080P maxed out settings.