I couldn't get a fully modular PSU in this budget however this will serve you well on the editing side and can handle light gaming at 1080p PCPartPicker part list:
http://pcpartpicker.com/p/3rJtLk
Price breakdown by merchant: http://pcpartpicker.com/p/3rJtLk/by_merchant/
CPU: Intel Core i7-4790 3.6GHz Quad-Core Processor ($289.99 @ TigerDirect)
Motherboard: ASRock H97 PRO4 ATX LGA1150 Motherboard ($88.99 @ Mwave)
Memory: A-Data XPG V2 16GB (2 x 8GB) DDR3-2400 Memory ($154.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($51.98 @ OutletPC)
Video Card: Gigabyte Radeon R7 260X 1GB Video Card ($99.99 @ Newegg)
Case: Corsair 200R ATX Mid Tower Case ($57.99 @ Micro Center)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($29.99 @ Newegg)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($15.63 @ OutletPC)
Total: $789.55
Prices include shipping, taxes, and discounts when available
I can go i5 for better all round pc though