According to techpowerup's testing in their 16 game test suite .... the 1060 6GB > 480 8GB
the 1060 3GB > 480 4GB
Problem is, you haven't provided a resolution ... at 1440p, the RAM figures in a lot more than it would at 1080p. At 1080p, the VRAM question is inconsequential.
Right now, the recent price cuts on the 480 make it an attractive purchase... at least at 1st glance... the PSU should be 100 watts bigger and you prolly want an extra case fan with the 480. The difference in power costs would be about $65 over an anticipated 3 year life span....
However looking at your build, I'd drop the 7700k since your MoBo can not take advantage of it and get a 7600. That puts $120 back in your pocket ... and leaves you with range of a 1070.
Cheaper, better and more powerful PSUs (saves $10):
SeaSonic S12II 620 $45
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
SeaSonic M12II 520 $45 (modular)
https://www.newegg.com/Product/Product.aspx?Item=N82E16...
If you can spring for some extra budget room...
-The Realtek ALC887 audio solution on your MoBo may leave you wanting more. I'd have selected a Z270 MoBo w/ ALC 1220 and a7600k. The MSI Mortar ($115) would take a 7600k and improves the audio solution to ALC 892
-An extra $22 would get you a SSD/HD ybrid which would speed things up a bit for $20
https://pcpartpicker.com/product/ftPfrH/seagate-interna...
Samsing SSD = 15.6 secs
Seagate SSHD = 16.5
HD = 21.2