Is this a future proof build?

Solution
Nothing is "future proof"
But, your build is excellent and comes as close as is reasonable.

If budget permits, Try to use a 500gb ssd up front. Defer on the hard drive if you need to.
A SSD will slow down and lose endurance as it fills up. With ssd prices declining, 500gb is very affordable.
Great build! But power supply is only so-so. This one is better quality:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-6600K 3.5GHz Quad-Core Processor ($244.78 @ OutletPC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($24.75 @ OutletPC)
Motherboard: MSI Z170A GAMING M5 ATX LGA1151 Motherboard ($169.99 @ Micro Center)
Memory: G.Skill Ripjaws V Series 16GB (2 x 8GB) DDR4-2400 Memory ($67.99 @ Newegg)
Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($87.00 @ Amazon)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($49.89 @ OutletPC)
Video Card: MSI GeForce GTX 970 4GB Twin Frozr V Video Card ($319.99 @ NCIX US)
Case: Corsair Carbide 400C ATX Mid Tower Case ($99.98 @ Amazon)
Power Supply: EVGA 750W 80+ Bronze Certified Semi-Modular ATX Power Supply ($48.99 @ NCIX US)
Total: $1113.36
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-27 12:27 EST-0500
 
Nothing is "future proof"
But, your build is excellent and comes as close as is reasonable.

If budget permits, Try to use a 500gb ssd up front. Defer on the hard drive if you need to.
A SSD will slow down and lose endurance as it fills up. With ssd prices declining, 500gb is very affordable.
 
Solution
Agreed that the concept of "future proof" is a mythical dragon not worth chasing.

However your build is pretty solid. The only thing I would change is your HDD configuration. If you have a significant future involved with this build, you run a significant chance of that drive failing simply due to age. A good way to prevent that would be to get two and put them in RAID1 or get three and put them in RAID5. If you can, consider using something other than the WD Blue series (which is now merged with the WD Green series if you see any WD Blue drives over 1TB in capacity they are rebadged Greens). For that sort of application, I would try to go with WD Red drives as a good compromise on price and capacity. Getting three 2TB WD Reds would yield you 4TB of storage immune from a single disk failure which has a greatly reduced chance of losing all your data compared to a single 4TB drive.
 
nothing is future prof that is right but most parts can last for a few years about 4 or 5 at best since in my case i have had to put with my 2600k in part because i dont feel there is a processor that gives me enought processing power to upgrade maybe the skylake but its still not the upgrade that meets my expectations also the videocard is probably going to change in 2 years o so can last for 3 years with luck