Mark, the startup community in NYC is thriving. It's a very exciting time to be in the NY tech scene. It's especially interesting as a CS student. Shoot me an email if you want to chat.
agree with max on this one. i'm at columbia and max is at NYU - i have worked with a bunch of NYC startups and can tell you that both the funding environment and the excitement around startups is second to none. we also have some great schools here if you're thinking of transferring.