Breakfast before Nat. Hist. Museum?
I'm still a Sarabeth's stalwart, though it gets some mixed reviews on this board. Isabella's is right across the street and has a sizable outdoor cafe, though I find it hard to like the places under the BR Guest empire; food is okay but nothing special. Barney Greengrass isn't as close (still in the neighborhood though - at 86th St., I think?) but is great for bagels, lox, sturgeon.