There is not much of a difference between the CPUs in terms of sheer performance; though, the Ivy Bridge's CPU is marginally
better. They are both really great quad-core processors, however I would be more inclined to purchase the Ivy Bridge CPU because of the lower power consumption...
I have the 3570K in my computer, and it is a great choice. You are dealing with a win-win situation here. http://www.tomshardware.com/charts/cpu-charts-2012/compare,3142.html?prod%5B5755%5D=on&prod%5B5760%5D=on
EDIT: I took the liberty of comparing the two processors upon myself.
EDIT2: I just realized you mentioned something about the graphics, to which I will respond with "no, you don't need a graphics card". This comes with the HD4000 integrated graphics (even better than the HD3000), which is even more of a reason to buy it. Unless, of course, you intend on playing games at really high resolutions, and expect a high frame-rate.