Looking for a good bistro? BLT Steak and it's sister restaurants (BLT Fish, BLT Prime) perfectly fit the bill. And since they are located around the country, you don't even have to be in NYC to enjoy them!
The menu is deceptively simple -- the bib lettuce salad or turna tartare are somewhat standard items -- but don't be surprised to find an interesting ingredient (a spice, or a vegetable) that you wouldn't normally see. If you're there for the steak, sample some different sauces. And don't forget the fabulous sides like truffled mashed potatoes or grilled asparagus. Looking for something new? Check out the weekly blackboard specials which change based on the seasons and currently available ingredients.
Having said all that, the real reason you want to eat at BLT is for the "bread" basket -- BLT's signature hot popovers. It's the gruyere cheese and the sea salt in the recipe that makes them so fabulous. You even get a recipe card so you can make them at home when you have a hankering for them (or get the recipe at Epicurious.)
Me? I'm just dying (or rather, DIETing) to get back there!