No, don't rent a car to get around New York City! It's the WORST way to travel in town!
I would suggest that you just take taxis, and let the taxi driver worry about the traffic and the route, and, best of all, when you get to where you're going, you leave the car behind and don't have to find a place, and spend a small fortune, to park it!
Trust me, if you were going to spend the money to rent a car anyway, then spend the money to take a couple of taxis instead, you'll thank me later!! ;-)
