You need a tier 1 CPU to go with the R9 290 GPU as per http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-5.html.
Thus the cheapest CPU on that list will suffice, AKA the i5-4440.
Unfortunately the PSU requirement for the R9 290 is at least a 750W PSU. Beware the 290 runs really, really hot.
I added a SSD instead of the HDD. MAssive speed increase that will not go unnoticed.
I also added a superior screen for approximately the same amount of money. Check it out...
Here's the complete list.
PCPartPicker part list:
http://pcpartpicker.com/p/s9qwpg
Price breakdown by merchant: http://pcpartpicker.com/p/s9qwpg/by_merchant/
CPU: Intel Core i5-4440 3.1GHz Quad-Core Processor ($174.99 @ NCIX US)
Motherboard: ASRock Z97M Anniversary Micro ATX LGA1150 Motherboard ($74.99 @ Newegg)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($63.99 @ Newegg)
Storage: Crucial M500 240GB 2.5" Solid State Drive ($98.94 @ Amazon)
Video Card: HIS Radeon R9 290 4GB IceQ X² Video Card ($259.99 @ Newegg)
Case: NZXT Source 210 Elite (White) ATX Mid Tower Case ($41.99 @ SuperBiiz)
Power Supply: Thermaltake 750W 80+ Gold Certified Semi-Modular ATX Power Supply ($59.99 @ Newegg)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($89.98 @ OutletPC)
Monitor: ViewSonic VX2452mh 60Hz 23.6" Monitor ($169.99 @ Amazon)
Total: $1034.85
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-01-18 20:30 EST-0500
PS. Rather go with 2x4GB RAM modules so you can harness the dual channel capapbility of the motherboard.