I've been to a lot of big cities but nothing compares to this one. We only had time to cruise around Manhattan but even that took us several days with hours of walking. It was very cool to see the neighborhoods that we've all heard about. Everywhere you look are countless restaurants, bars (which close at 4am - big trouble...) and places to shop. It's a very clean city with almost no garbage on the streets and no panhandlers hassling you thanks to the former Mayor Guilliani (sp?).
The buildings are enormous and so tightly packed in that there isn't a square inch of unused space. But somehow, you don't feel overwhelmed by this. The people here were a real surprise as well. I had always heard that New Yorkers were a harsh breed of folks and this wasn't my experience at all. In fact, I found them to be very friendly and hospitable.
Another very noticeable thing here is that the people in NY are eternally stylish. Everyone was perfectly attired in some funky outfit with matching accessories. I had never believed that people actually wore the clothing that I've seen on fashion television but boy, I was wrong.
The traffic is crazy. Not only congested as you would expect but the drivers are mad, especially the cabbies. People completely disregard lane lines while speeding down the boulevards (a la Montreal) and pedestrians ignore traffic signals and walk between the crush of vehicles as if they owned the place. Apparently, there's a law in NY against honking because so much of Manhattan is residential that nobody would ever have any peace if all the folks were to use their horns.
There are a million people on the streets at any given time and you're constantly fighting crowds, even on a Sunday morning.
There is way too much to say about NYC so all I will say is that you have to come and check it out yourselves. It's unbelievable!