Well, depends... the 560Ti is the current bang for buck price-leader, neck and neck with 6950 1GB versions. Some of the sales now make a lot of sense - under 200$ for a 560Ti? Yes please. The 2GB of the 6950/6970 IMO don't make sense unless you have a huge screen with killer res - a 30" with 2560x1600, or something like that.
Some games are better on the 560Ti, some games are better on 6950 - depends on what they optimize it for. Traditionally, EA games optimized for Nvidia, Valve likes ATI.
Also, I like the Nvidia drivers much more than the ATI ones. And they use less power and in general are quieter than ATI products.
@ Ulic - you should be fine... but maybe time for an upgrade soon? 260's are getting pretty long in the tooth.
EDIT: Or Hell, get two of these:
Gigabyte 560 and SLI them. Better than a GTX580 in performance for less.