I poked around on PCPartPicker, but I really think that in order to get the best content creation performance, you're going to need to go a little over your budget, wait if you have to. You can migrate the hard drive to the new computer to use as a boot drive and use your current monitor (assuming you're on a desktop right now, you should be if you're a content creator).
What I built here costs just $100 more than your budget, but that's worth it for the mile of performance increases over what a 960/950 and an i5 would do.
http://pcpartpicker.com/list/xFqLPs
SPECS:
i7-6700K - Overclockable SKU.
Corsair H80i - All-in-one sealed no hassle watercooling loop.
ASROCK Z170 - For overclocking, better performance per dollar.
G.Skill Ripjaws X 16GB RAM - 16GB or bust.
Western Digital Caviar Blue 1TB - 1TB or bust.
EVGA GeForce GTX1060 6GB - Mid-range performance king.
NZXT S340 - Actually just this so you can mount the H80i.
Corsair Builder 500W 80+ Bronze - Efficient and enough wattage.
NOT INCLUDED
Monitors, peripherals, operating system, SSD.
Again, just migrate your current drive to the new computer to serve as the boot drive. An SSD is a luxury, and on a budget high-power computer like this, you'll still be free to get one down the road.