If you have a good 500w+ power supply with room for GPU's over 300mm:
Video Card:Gigabyte Radeon R9 280 3GB WINDFORCE Video Card ($187.98 @ Newegg) Total: $187.98 Prices include shipping, taxes, and discounts when available Generated by PCPartPicker 2015-07-21 14:06 EDT-0400
If you have a PSU 400-450 watts power supply:
Video Card:EVGA GeForce GTX 960 2GB Video Card ($194.99 @ SuperBiiz) Total: $194.99 Prices include shipping, taxes, and discounts when available Generated by PCPartPicker 2015-07-21 14:07 EDT-0400
All good R9 285/380 models (They are the same) cost between 200-215 dollars. However performance is really similar to the GTX 960 which is 195 dollars as provided. I would suggest GTX 960 over both.
I'm kinda new to building a pc so sorry if this is really dumb but would the 960 still be the best for an AMD cpu or is there another one that's better?