A: Maybe. It really depends on what you want to do.
If you want to work on big studio pictures then the answer is yes. If you live in the United States and you want regular work in production, it would be a wise idea. New York City has enough work in film and television to support regular work but it doesn't even come close to comparing to what is available in Los Angeles. It's not even in the same league.
Many recent film school graduates go to large cities in pursuit of work. This is a poor idea for the most part. Cities like Seattle, Portland, San Francisco, San Diego, Denver, Chicago, Miami, Austin have small, boutique film scenes but really nothing to speak of aside from the usual corporate/industrial and commercial work you will find anywhere.
That being said, many film school graduates flock to Los Angeles. The city is full of opportunity if you wish to work in film. If you know what you want and pursue it with single minded determination you will do fine. However, it is a highly competitive place for the above-the-line positions and rife with insecurity and cut throat personalities. If you want to work with the best professionals in the business, go to Los Angeles.
If you want to create your own movies then you might be best staying far away from the overpowering herd mentality of Hollywood. The internet is really facilitating the success of filmmakers who wish to operate outside of Los Angeles. If you are a director, writer or producer and feel confident using the Internet to your advantage then Los Angeles is not the inescapable vortex that it once was.