I have the gtx 580 and its the real macoy very good fps at max out settings so the 590 would be my choice but I think that you would be fine with the gtx 580 a i7 2600k.....and spend some money that you save from buying the 580 and buy a good keyboard and mouse (i have the steelseries sensei and its the best mouse i had).
Bottom line if you really want it I would go for the 590 but thats me Im a nvidia fan both are top end cards so you can go wrong.
I have the gtx 580 and its the real macoy very good fps at max out settings so the 590 would be my choice but I think that you would be fine with the gtx 580 a i7 2600k.....and spend some money that you save from buying the 580 and buy a good keyboard and mouse (i have the steelseries sensei and its the best mouse i had).
Bottom line if you really want it I would go for the 590 but thats me Im a nvidia fan both are top end cards so you can go wrong.