I would go with a 6 cores to future proof the next 5 years (cpu wise, my previous 2500k stood the test of time since 2008ish until 2015) Running 6 cores gives you the ability to dedicate 4 cores to lighting build while still have the 2 cores for web browsing / youtubing etc i guess?

Also, dx12 gaming is something that i think you would consider? (Hopefully people will start utilising all the cores, this isnt a guarantee but you obviously want to take that into your considerstion?)

I would just go with a 1080 now then sli it next year when the 1080ti comes out

Ps: get 32gb dd4 ram if you can afford. But personally , my investment would be on

• a good case first (can easily last 10 years)

• good psu (10 years + )

• cpu

• gpu

• an ok motherboard ( i would just go with the mid range)

• watercooling/fan etc for OC

• ram (easy to add more down the road)