There is no best way. Like mentioned, the only way to do it without hurting your credit is to bring your checkbook and cut a check for the amount you're upside down. The other options (short sale, deed in lieu of foreclosure or foreclosure) ARE going to hurt your credit. There's no two ways about it. There are varying degrees of how bad it's going to hurt, but it'll hurt nonetheless. If you don't have the capital to make up the difference, continuing to rent the home is your best bet.
I'm a little late to your party, but since no one answered, $135,000
We're in late December and there is still no MLS activity on that property.
If you're still looking and want a third opinion, I'd be thrilled to help you out!