The London Bar at the London NYC Hotel is great. Good cocktails (try the Diablo - i think that's it), good people. (Gordon Ramsay's restaurant is there, but don't worry - that's the formal side. The Bar is separate.)
Perfect. I'd head to Kellari Taverna on 44th between 5th and 6th. The atmosphere is gorgeous and they have nice small plates/snacks/mezze. I don't recommend eating dinner here, as I feel that there are MUCH better Greek restaurants in town...but the space is truly stunning.