Compare the differences, essentially they are a 200MHz clock diff (3.2/3.6 vs. 3.4/3.8GHz), the ability to overclock (non-K vs. K), and the on-die graphics (2500 vs. 4000). For $15 (currently $199 vs. $214.99 on newegg), I would say it's worth the 200MHz, but that's your call. I own the 3570K and have it overclocked to 4.6GHz, with a Corsair H70 cooler. Even if you aren't going to overclock, its a very nice chip, and the $15 difference is negligible at this price-point. If you don't care about the $15, get the 3570K, you don't need an aftermarket cooler unless you're going to overclock (and for $15 having the option to overclock in the future even if you DON'T plan to, is more than enough to warrant the difference, ON TOP of the base speed diff.). Just my 2 cents.
Which result are you leaning towards? As I said, personally I would get the 3570K even if I wasn't overclocking just for the slightly higher stock speed, and the unlocked multiplier for possible future use. If $15 is a make or break amount for you, then get the 3470. The 3570K will still work with the H77 mobo, but as far as future flexibility goes, it again comes down to whether you are thinking of upgrading/overclocking in the future, or just want something that will stay the same as when you built it.