I discovered this clip from Nightline which I found to be particularly interesting as it covers the way that some are adjusting to the shift in the housing market. I like that they even interviewed someone that was choosing to strategically default on their mortgage (i.e. walking away) but I wish they would have went more into it.
Lenders are now pursuing borrowers that deem to have walked away because, in most states, they have the right to collect on the balance. Every state is different but here in North Carolina, your lender has the right to sue you for the balance for up to 10 years after the foreclosure. If you must leave and you have a hardship, the best solution is to negotiate with your lender a deed-in-lieu of foreclosure or sell the home through a short sale.