This is an interesting philosophical question that I've pondered on before: When is a man, if ever, justified in breaking the law?
It depends, in part, on how one defines the function of government to begin with, and whether the state exists to serve man or man exists to serve the state, of course. One must also mind that niches such as 'defensive murder' are typically covered in law; a person is not usually punished for defending themselves against another trespassing on their property who has just killed their entire family and who has shown definite intent to kill the person in question who has therefore murdered the offender. So to say 'in defense for my life' directly is not really a valid answer to the question, unless we're also examining Christian laws, which I am also open to if Christians would like to add their two cents on whether it's ever okay to break one of the ten commandments. Interpret this question however you can best answer it.
I'll add my own two cents later on, I don't want to affect anyone's answer with examples right away.
The first point to make is that ultimately, there is no absolute morality. What we depend upon, then, is that, on average, people will typically tend to make moral decisions that most others agree with. For most things, this is the case. Ultimately what it comes to, then, is each individual person will make their own decisions for when it's okay to break the law, and the rest of us have a duty to stand up to those people whom we feel make bad decisions in that regard.
My personal belief is that first of all, it's not "that bad" to break a law that doesn't hurt anybody (whether physically, emotionally, economically), or even have significant risk of doing so. You always have to weigh against the potential downside of the legal consequences of the action, but this sort of law-breaking I wouldn't consider that bad in the main.
And we most certainly should break the law in situations where the law itself is causing harm to people, such as discriminatory laws, if breaking said law is effective. In many cases, civil rights protests fell right down this alley. Today the big civil rights issue is gay rights, though there aren't many situations in which it would actually be effective to break the law as a result (it's not exactly possible to get married illegally in any way that matters, after all). But here's a recent example of a bit of law-breaking (technically trespassing) that was, in my view, 100% the right thing to do: http://www.huffingtonpost.com/2009/07/19/mass-kissin-protest-at-mo_...
Fortunately the church, in this case, did the sane thing and didn't press charges.