Ahh, didnt notice that the i7 2600k package came with 8 Gig ram. Should I just buy an extra 8 Gig ram then?

Been doing some searching online. Lets say I wanted 4 screens on 1 computer, would nVidia 3GB GTX 580 be needed? Could I go for 2 other video cards with close to the same performance as the 580?