I'm planning on building a new system sometime around December and was wondering which would be better, 8 GB or 16 GB of ram for the system.

Proposed System

PSU: Corsair AS860 (860 watts)
CPU: Intel i7 Skylake 6700K
MB: Asrock Z170 Extreme 6+
Memory: G.Skill Ripjaws V Series DDR4-3200 (8GB)
GPU: XFX R9 380 4GB
CPU Cooling: Corsair H110I GTX Water Cooler
SSD: Samsung 850 EVO 2.5" 500GB SATA III

I'm just debating whether I need 8 or 16 GB of Ram. Any thoughts? I should mention that there will be some heavy gaming.