I really think that you are being completely rational and smart in thinking through the financials of it. My wife has just about that same situation (except she is a lawyer), and the loans kill us. Here is the problem with 200k in debt making 40-60k. Basically you will go on income contingent loans (without it you will be paying roughly 2400/month, which after taxes will leave you with an unlivable amount). This means that you will pay out enough to keep you 20% over the poverty line (roughly 1100/month). Paying income contingent is very manageable. You will be able to live in a decent place and not have to eat spam everyday. However, that 1100 wont even cover your interest so your loan will actually grow even though you are paying as much as you can. After paying over $1000/month for 2 years, my wifes loan has actually grown $800 from the day she graduated.
I really dont want to deter you from making a decision, but I do know what it is like to be going through these massive loans.