That said, I put the full budget into a GPU. With the release of the GTX 970 and 980, prices have DROPPED on just about all other previous "top cards"....
The GTX 770, 780, 780Ti are all discontinued and selling for as little as 1/2 what they were less than a year ago (great bargains)
Same for AMD 280, 280X, 290, and 290X, while not "Officially" discontinued, their prices are at an all time low too.
Buy the highest end card you can afford in those listed above.
NOTE: Be sure you have at least a 650watt power supply to support these (yeah, could be by with less on the NVidia's but, just want to assure your aware don't try these with too small a power supply)