Brunch after Metropolitan Opera Tour
You haven't given us anything to go on in terms of the *kind* of brunch you are looking for, i.e., breakfast foods vs lunch dishes, sit-down vs buffet, etc. That said...
Compass, on 70th St., b/t Amsterdam & West End Avs., is quite close to Lincoln Center. Though we've not done brunch there, we have had dinner and, since the food was excellent, I suspect the brunch will be as well.
Eleven Madison Park is our favorite upscale brunch place. Chef Humm's food is as superb at brunch as it is at lunch and dinner. Service is always perfect, and the room is gorgeous.
For recommendations in the boroughs, I suggest you post on the Outer Borough board.