Keyword here is "Gaming"
To my eyes, 4670k which i have currently in use, works exactly the same as my test 4770k in gaming.
If it was pure gaming, i'd say go for 4670k. Absolutely not worth the extra money.
In workstation usage, such as rendering etc. etc, difference is considerable.
So answer to your question is 4770k, as simple as that.
I game and video render. I have a i7 4770K in my computer, while my friend has the i5. Gaming performance, we see very little difference (i may get 1 extra FPS here and there.) But video rendering is where my i7 shines. When using handbrake, his i5 renders about 250-300 FPS, my i7 gets double that, 550-600.