I second and third La Madeleine, La Bergamote, and Billy's. I just picked up some croissants and brioche from LM this morning to take home for Easter. I had a couple nibbles of the almond brioche, and it was delicious. Billy's is my favorite bakery for old-fashioned cakes and pies.
Not sure what you are looking for - but I believe La Madeleine is on 23rd between 5th and 7th - I've heard talk that they are moving, so you might want to call first. They have lovely macarons, croissants, pain au chocolat, pastries, brioche etc. There is also La Bergamote at 9th Avenue and 20th Street.