In terms of theft. It depends upon the manner of the theft. If one follows the banks required precautions then one is usually covered (in the UK at least). If one does not then one is not covered -- although I'd agree that banks are increasingly not covering people if they can avoid doing so.

I was more thinking of institutional theft (i.e. embezzlement). I'm almost certain my bank won't just vanish the money I have lent them through my savings account. Of course the same cannot be said of "Random Investment Company Name" who was recommended to me on a forum/down the pub. As yet (and I hope that this changes) non of the bitcoin service companies have risen above this level of trust (for me personally).

EDIT: Added fact that my assessment of trust is my personal subjective opinion and shouldn't be taken as a fact.