better gpu, better gaming (if that's what you're doing). with a 3470 you would be getting a motherboard with a locked multiplier (ie H77, B77, etc) which could entail more savings. if you can, bump the gpu to a 7870XT (TahitiLE)
crysis and battlefield are GPU intensive games and the only difference between the 3470 and 3570K is the unlocked multiplier and 200MHz. If you get the 3570K, you'll spend more on the MB and would have to get a decent aftermarket cooler. IMO, you're better off with the i5-3470 and the 7870 (or possibly the tahiti le version)