David Pogue's phone was stolen. Using Find my iPhone, an army of Twitter followers, Gizmodo.com and the Prince George's County police, he was able to get it back.
In 2007, my Samsung Blade A800 was stolen. I'd installed GPS tracking software on it for a pet project. I was able to locate the house it was at. I called the cops. They were only willing to fill out a report so I could file the loss with insurance. They were completely unwilling to investigate or even knock on the door of the house that GPS said the phone was at.
I got billed $400 from Sprint for downloaded games, songs, and ringtones.