The only time I use real people in stories, rare even at that, are when they're extremely minor (one time appearance in the entire tale) or a mention. For instance, a character could mention a song by Nickelback, or see Skillet on stage, or go to a book signing by famous authors. One story where I had to use real actors/singers was when I wrote a fanfiction regarding this crime organization that was attempting to kill every celebrity on the planet, the main group had to stop this somehow.
I think there's a difference between using real people as main characters in a story and twisting them around into relationships and whatnot versus giving them one time appearances or casting them as minor people that may not be that crucial to the flow of a story. The latter, of course, being preferred if you have to use real people.