The Metropolitan Opera has lower price tickets available for most performances. The top level is reputed to have the best acoustics in the house, as the sound is carried up and across the roof. Actually, the acoustic are fine at all levels. Performances are every evening except Sunday, and Saturday afternoons.
See the Metropolitan Museum also. It's one of the world's great museums. about 6 years ago
I also highly recommend the Hilton Garden Inn on the corner of 47th St and 8th Ave. it has a fine French bistro restaurant (Pigalle). Hilton Garden Inns are not to be confused with Hilton hotels, which are more expensive and, in my opinion, more staid and formal than the Garden Inns, which are part of the same Hilton chain. about 6 years ago