I think it depends on what you are looking to get out of it... we have the Snap N Go with a Snugride carseat. It works perfectly for us. We can break it down to take a cab or go on the subway. There's no way I personally could do it all with a "real" stroller. Plus I can manage by myself (getting from UES to let's say Midtown) via subway all by myself. We always buckle the carseat in a cab too, so having it with us is a huge plus.
I had a look to most of them, especially because I'm in Midtown and I walk to everywhere, therefore I am getting a Bugaboo Cameleon. Is the lightest and is very safe and comfy. ;-)
I used the Kolcraft Universal Car Seat Carrier until my daughter was about 6 months and then switched to the Maclaren Triumph which is awesome and super light. I just wish the seat reclined a little more.
Re: good stroller for the city?