I think Murphy should go to New York and play for Mike D'Antoni.
He'd be a nice stretch four sandwiched in between Amare and Carmelo Anthony. The Knicks big man rotation is very weak outside of Amare so there would be plenty of minutes available for him. He could easily get 30+ minutes a night there either as a starting PF or a backup combo big man (behind Turiaf/Amare).
With the Knicks uptempo offense and weak rebounders, he could put together (statistically) a very impressive season and use that to get another big contract the following the summer.
If I am Troy Murphy, under no circumstances would I consider returning to Boston. Not enough minutes available. I'd be looking for anyone that will give him close to 30 minutes a contest so that I can get my career back on track + earn another big contract before it's too late.