if you like REALLY high fps, go with the 1080p solution. if you want a better looking overall setup, go with the 1440p setup, but theres another option around 2000 bucks:
PCPartPicker part list:
http://pcpartpicker.com/p/dhRcVn
Price breakdown by merchant: http://pcpartpicker.com/p/dhRcVn/by_merchant/
CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor ($219.98 @ OutletPC)
Motherboard: Gigabyte GA-Z97X-SLI ATX LGA1150 Motherboard ($116.75 @ OutletPC)
Memory: G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory ($62.99 @ Newegg)
Storage: Kingston SSDNow V300 Series 120GB 2.5" Solid State Drive ($53.98 @ OutletPC)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($52.85 @ OutletPC)
Video Card: Asus GeForce GTX 970 4GB STRIX Video Card (2-Way SLI) ($348.99 @ NCIX US)
Video Card: Asus GeForce GTX 970 4GB STRIX Video Card (2-Way SLI) ($348.99 @ NCIX US)
Case: NZXT H440 (Black/Red) ATX Mid Tower Case ($108.99 @ SuperBiiz)
Power Supply: Corsair RM 850W 80+ Gold Certified Fully-Modular ATX Power Supply ($129.99 @ Amazon)
Monitor: Asus PB287Q 60Hz 28.0" Monitor ($565.99 @ Amazon)
Total: $2009.50
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-01-04 11:17 EST-0500
this is a great 4K 2000 bucks setup. 2 970 is great for great 1440p and lite-good 4k gaming, hence the 4k display.
hope this helps