After one day on the east coast I have a slight but perhaps not unbiased view of the differences between LA and NYC. I like LA alot but I must say that I love NY and I think it happened the instance when I saw the Manhattan skyline. There are pros and cons with both places of course. LA is hot and NYC is hot and humid. LA wins that one. It is easier to move around in NYC and the feel of the city is more European which I like. Round two for NYC. The style of the New Yorkers are more to my taste but the Los Angelers are more friendly (could of course have something to do with that I spent most of my time in West Hollywood).
So in a perfect world I would take the climate of California and the people, suit them up in a slightly different style and dump them in New York. That would be the recipe of a really good city.