You don't need more, I have that case without extra fans and the airflow is already good. But suit yourself I guess.
PCPartPicker part list:
http://pcpartpicker.com/p/WGGq99
Price breakdown by merchant: http://pcpartpicker.com/p/WGGq99/by_merchant/
CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor ($219.88 @ OutletPC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($28.75 @ OutletPC)
Motherboard: ASRock Z97 Extreme3 ATX LGA1150 Motherboard ($104.99 @ Newegg)
Memory: G.Skill Ares Series 8GB (2 x 4GB) DDR3-1866 Memory ($72.97 @ OutletPC)
Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($129.98 @ OutletPC)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($49.88 @ OutletPC)
Video Card: EVGA GeForce GTX 970 4GB FTW ACX 2.0 Video Card ($378.99 @ SuperBiiz)
Case: Fractal Design Define R4 w/Window (Black Pearl) ATX Mid Tower Case ($79.99 @ Newegg)
Power Supply: EVGA 750W 80+ Gold Certified Fully-Modular ATX Power Supply ($108.99 @ SuperBiiz)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.98 @ OutletPC)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($89.98 @ OutletPC)
Case Fan: Corsair Air Series AF120 Quiet Edition (2-Pack) 39.9 CFM 120mm Fans ($23.98 @ OutletPC)
Case Fan: Corsair Air Series AF120 Quiet Edition (2-Pack) 39.9 CFM 120mm Fans ($23.98 @ OutletPC)
Total: $1329.34
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-01-12 14:58 EST-0500