I'd steer clear of the 560 448 at the moment. It's too expensive for what you get: performance wise it sits perfectly in between the 570 and 560ti, yet costs £50-60 more than a 560ti and only £20-30 less than a 570. You may as well throw in the extra and get a 570. If the 560 448 was around £200 it'd be perfect.
If I had some money (and I sincerely wish I did) I'd plump on either a 570 or a 6950.
If I had some money (and I sincerely wish I did) I'd plump on either a 570 or a 6950.