Uncle Sam Want's YOUR help building him a compy)

Nvidia is currently the best option right now for GPUs if you want the best performance (GTX 970, 980). AMD however is coming out with a new line of GPUs in 2015 (3xx I think) which will probably perform better than the 900 cards (unless Nvidia releases a 980 Ti). That's usually how it works, Nvidia is best one year, then AMD, then Nvidia, etc