Yes, but I believe the GTX 560 has more room for an OC, runs cooler, and doesn't make as much noise.
Either way they are both good, its more of a personal preference thing. The Core2Quad is still an awesome chip; one of my friends is running a Core2Duo still and he is running most of the games he plays on the highest graphics they go, even with a GTX550Ti.
I would go with either the GTX560 Ti or a Radeon 6950. Honestly I would just get whatever one you can find for cheaper or whatever style of cooler you like better. They are more or less equal in performance.