Buy new or used bike?

I have a low budget for a hybrid bike (no high demand, just commuting). I visited some bike shops and the lowest priced are like $300 or so for something like a Raleigh Detour. If I buy a used bike, a good brand like Raleigh or Trek or Giant will cost at least $150 it seems--and I may well have to pay some $$ for some repair/tune-up since it's used, so probably ending up $200+. These, and considering the resale values, seems a new one is a better option? The one negative of a new one is: I'm in NYC which is full of bike thieves.