Processors do not prefer certain cards. If you want advice on what card you should get we will need a lot more info like the rest of the system, your resolution, budget and what you will be using the card for.
the 2600k does nothing that the 2500k wont do for gaming .... so thta can give ya an extra $100 to send on GFX
At 1920 x 1200, I recommend AMD cards at the < $200 price point and nVidia at all points above $200. The enw 560 / 570 hybris looks like a game chnager