Can't go wrong with a 460(1GB)/560 really. Maybe stretch to a 560 Ti, excellent cards.
Upcoming games like XCOM, Carrier Command and War of the Roses state a minimum of 2-2.5GHz dual-core, with quads recommended. Dishonored actually requires a 3GHz dual or decent quad.
That CPU can still hack it for a bit longer, but dual-cores are coming to the end of their useability for gaming. Think a 460/560 makes a good fit, and you'll be plenty happy with that. On a 460 1GB myself.
