RE: NYC with newborn
We took Sarah to Manhattan when she was 8 weeks old. I wouldn't take a baby to the theater, but I wouldn't think twice about bringing one to ANY museum. I actually find museums to be good places to nurse, they always have hidden benches, nooks and crannies, and small, unvisited side rooms.
As for restaurants, again, depending on her personality, I wouldn't have any qualms. If she is really fussy or colicky, then maybe not, but of she is generally contented in the evenings, then sure!
Beth, mom to older DD (8/01) and younger DD (10/06) and always missing Leah (4/22 - 5/1/05)