What should I upgrade first?

[Hypoc223]

From a GTX 950 2GB -> GTX 1060 6GB
or
From a i3 4160 3.6GHz -> i5 Skylake/Kaby Lake

 

[clarkjd]

From a GTX 950 2GB -> GTX 1060 6GB
or
From a i3 4160 3.6GHz -> i5 Skylake/Kaby Lake

Depends on what you are doing with it. For gaming, Graphics card. For other workloads, CPU.

 

[Isokolon]

upgrading the i3 4160 -> Kaby Lake is not worth it.
rather just get an i7-4790 or sth like that

both upgrades are justifiable.