In the US ;)

I'd do it for a cool million, possibly less. There's plenty of places around the US, let alone the world, where returns around $50,000 yearly or less would provide a comfortable life. Add the ability to supplement that with whatever work you care to perform and you can be more than comfortable.

EDIT: On further thought, I'd go for much less, I think. It's really just a comparison the money offered against A) the amount I'd expect to earn in those 3 years, B) expected loss of lifetime income due to the time lost and/or resulting stigmas, and C) personal discomfort/inconvenience of the lockup time.

Hard to figure the latter two, but I expect even half a million would tip the balance in my case.