http://www.anandtech.com/bench/Product/309?vs=292
out of the 40 game/performance tests, the GTX480 wins 23
actually its 24 wins, one of the tests is "lower is better" so the GTX480 is the better card.
That Anandtech bench is a load of rubbish for comparing Nvidia VS ATI and well you know it. Also, you will only promote Nvidia for some creepy reason. I would never take advice from you as you cannot be trusted to be reliable due to the completely pointless way you follow and promote Nvidia in anything graphic card related. Until you sort that fanboi rubbish out, you're useless IMO in the graphic card section

. Shame really but that's the choice you've made.
I'll say one thing though, you've actually been a pleasant fanboi in this thread for only promoting Nvidia and saying nothing negative about the 6950 (ignoring it).
Hawx = Favours Nvidia heavily.
BattleForge = Favours Nvidia heavily.
Civilisation V = Favours Nvidia heavily.
Dirt 2 = Favours Nvidia.
Stalker = Favours ATI
Take the above into consideration Stulid and now understand why I'm posting this. It's because you knew fine well that it wasn't a fair benchmark. Why not use several benchmark reviews?.
To the OP. I'd go for the 6950 or GTX 480 at your resolution. Yes the GTX 560 plays fine for most at 1920x1200 but you can start to see the GTX 560 buckle a little bit on a few titles at this resolution, even more so when a bit higher on selected titles too. If future gaming would be a factor then this is one thing I would take into consideration.
As for the GTX 480 or 6950, well I think both cards are very similar but as one is more power hungry, generates more heat, and is a little bit more noisy on top of becoming EOL, I think it sways towards the 6950.
I'm actually thinking of getting a GTX 570 but not for the gaming aspect of it as it would be a pointless side grade, it's because I can only select 1600x1200 on my gaming CRT with ATI's driver. When testing a 9800GTX for someone 2 months ago I could select 1920x1440. So it's only for that and I'm disputing whether paying £60-80 is really worth it.
I only mentioned this to show I have no preference to what manufacturer I use in my rig. Both companies are great

.