Great lunch in mid 40's?
I'd go to the Diamond Dairy Restaurant (4 W 47) located on the mezzanine above the National Jewelers Exchange. Cheap retro food with good fish, and the ambiance is exceptional.
More expensive is Wu Liang Ye (36 West 48th Street, 398-2308), a Sichuan restaurant owned by a Chinese conglomerate that have excellent and unusual (for New York) chow.
Cheaper is Yum (44th between 6th Ave & Times Square), a lunch counter Thai with an amazing duck salad.