There are several factors that you need to consider. First of all, our current housing trend doesn't show any signs of changing anytime soon. Every market is different, but the avg rate of market depreciation for the N. NV is is around 2% a month (based on past 6 months of sales). So if the market continues on its current path, you may be looking at a much lower value. Also keep in mind that when we do see a rebound, it will be nothing like what we were seeing during the boom. You may very well have to wait several years before you recoup your losses.
However if your decision is to sit on it as a rental, you will want to make sure you are at least generating some income from it. If you're current interest rate will not allow you to justify renting the property out, then you may want to see if it is possible to refinance the current mortgage.
There are also several other options that may be available to you. I'd be more then happy to offer you a no obligation consultation to discuss you current situation. At the very least, you may walk away with more information to help you come to a decision.