City is my favorite team; I've yet to start a CM with them but may do so soon and I will probably use that exact formation based on their personnel.
As far as the original question, the formation I use the most is the 4-3-3 (False 9). The False 9 refers to the lone striker who instead of waiting for the ball to be passed to him, instead drops deep and drifts around the pitch in search of the ball. You need a centre forward who can pass and has good attack positioning. I also use the trendy 4-2-3-1 which works just fine.