When in New York, you have to go to a rooftop! It is the best way to enjoy the views while sipping on a Cosmo.
My personal favourite is 230 Fifth.
When getting there it can be slightly confusing as you are queuing to enter what seems to be a regular apartment building.
It will worth the wait as once at the top you will be rewarded with the best view of the Empire State Building. Oh, and decent cocktails!
The place is very big so if you arrive early you can have good chances to grab a table. It does get really busy around end of business day (5pm) so if you can, head there before.