Firstly, I'm sorry for taking soooo long to respond. I've been moving into my new place and things have been hectic in general.
To answer the question--the $600 is the co-op maintenance fee. This includes heating, water, sewage, trash removal, and property taxes; the $600 is an upper estimate (it's actually around 575) and is pretty normal for a co-op in NYC, although it seems like a lot.
I am planning to pay off the mortgage asap. My #1 goal right now is paying that off ASAP; if anyone thinks I should defer and sock the money into other things, I'd love to hear your input.
Regarding health insurance: there are plenty of charity clinics and free hospital services. I am fairly healthy now so this isn't a major concern for me. (I haven't really needed to see a doctor in 5 years). My wife also plans on working so I'm hoping that I can get insurance through her until socialized medicine trickles down from Vermont to NY State, which I think will happen in the next decade.
m741: Investment is indeed an issue. I have some experience, but it isn't very good. I was badly burned in 2008 on stocks and have not wanted to get back in the market since. I have had much better experience with real estate, which is one reason why I bought this co-op. I'm quite sure it's a good investment and will appreciate considerably, but I want to calculate assuming that I stay here, since my wife loves the apartment.