As predicted, it appears HRC has won Nevada. Perhaps the biggest story though is Edwards' miserable showing, coming in right now at an anemic 5%. It's clear that his window has closed. There's no point in him staying in. That said, there's not much point in him getting out either. Being retired so to speak, he doesn't have a political office to fall back on.
The smartest thing he could do, in my opinion, is to get out and go whole-hog for Obama. I'm sure he's toying around with being a kingmaker at the convention, though this scenario seems unlikely. The race will likely "tip" well before then. Probability-wise, he's at the peak of his ability to influence the race. Jumping out now and endorsing Obama would be significant -- particularly before South Carolina. He therefore has a fleeting opportunity to leverage his influence to get something in an Obama administration.
Endorsing HRC is not an option. He's hit her too hard, well beyond the point of no return. Likewise, staying neutral gets him nothing. HRC would give him nothing either way, and Obama would have no reason to help Edwards if he stays on the sidelines.