This will get you going, and it has a lot of room for upgrades.
PCPartPicker part list:
http://pcpartpicker.com/p/3ArLu
Price breakdown by merchant: http://pcpartpicker.com/p/3ArLu/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3ArLu/benchmarks/
CPU: Intel Core i3-4130 3.4GHz Dual-Core Processor ($118.97 @ OutletPC)
Motherboard: Gigabyte GA-B85M-D2V Micro ATX LGA1150 Motherboard ($53.18 @ Newegg)
Memory: Crucial Ballistix Sport 4GB (1 x 4GB) DDR3-1600 Memory ($36.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.98 @ OutletPC)
Video Card: XFX Radeon R9 270X 2GB Double Dissipation Video Card ($179.99 @ Newegg)
Case: Cougar Solution (Black) ATX Mid Tower Case ($34.99 @ Newegg)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($34.99 @ Micro Center)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($84.99 @ NCIX US)
Total: $599.08
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-04-28 23:08 EDT-0400)
Getting an i3 now allows for you to upgrade to an i5, i7, or Xeon later
You can add 4GB more RAM at any time. It's easy and takes about 60sec.
You can add more storage if needed.
That's a tried and true case that has good cooling and a lot of room for more fans and hard drives.