I have a beautiful view from my balcony on the 22nd floor in Cliffside Park facing the river at around 100th St in Manhattan.
Last year there were a lot of people watching the fireworks from the piers near the new AMC movie theatre they put up along River Road. But you'll have to get there early because it was a zoo last year. I'd never seen so much traffic in that area in my whole time here. You could also probably try the Port Imperial ferry area but again you'll have to get there early.
Last year, the cops only let through local residents because of all the traffic.