FX 6300 + Asus R9 280x 3GB
A powerful GPU is more important than the CPU - well depends what games you're playing. If you're playing Minecraft - then it's CPU over GPU. But if its BF4, COD Ghosts, Crysis - then go with the R9 280x. The 3GB VRAM will help you game with a large screen resolution, and it'll help with games overall.
GPU Benchmarks: http://www.kotaku.com.au/2013/11/battlefield-4-benchmarked-is-your-pc-up-to-the-task/