Can't decide to sell & buy

So I'm stuck trying to figure out if I should sell my unlocked 6950 (MSI TF3) and go with a 7950 or 7970. I game on a 1920x1080 60Hz monitor and just want that extra power to fully max games with butter frames, but I'm not sure if it's really worth the money. I've had this itch for a few weeks, but am just undecided. I'm just looking for some push in a direction. I don't want to crossfire due to not wanting to buy another PSU so another 6950/6970 is out. Any help/advice is appreciated.