While people are starting to realize that a relationship with a dog is about being a respectful leader, consistency, communication, and teaching a dog what TO DO instead of what NOT TO DO (and no longer focusing on the dominance myth), I still have clients who sheepishly ask if their dog should be sleeping with them on the bed. My reply? Of course, as long as it is safe for you and safe for the dog.
Dogs who urinate in the bed, or keep their owners awake with snoring, shifting, or self-grooming should probably sleep elsewhere. Dogs who may hurt themselves jumping up and off of the bed should probably sleep elsewhere or have the appropriate stairs. I once traveled with a snuggly Dachshund who burrowed under the covers but would growl at me when I repositioned myself during the night. He ended up sleeping elsewhere.
If you are sharing a bed or couch, and your dog tends to be pushy in nature, I would definitely recommend training him to wait for permission to get on the furniture.