If you like sushi, great Japanese food, and people-watching, go to NOBU. The downtown location is still the best. I go there at least once every other week and I have never experienced a less than stellar time.
Slip the maitre-d a $20 and you'll get a nice table out-of-the-way if you want to keep it nice and romantic. Slip him a $50 and ask to be put front-and-center and you'll most likely rub elbows with some top notch celebs!
But, on a Fri or Sat night you'll NEED a reservation to even look at the front door. And those tips I mentioned about for table selection will need to be tripled (at least) on a weekend.