I came across these stories today and decided to share my experience. Although I don't think him to be a ghost I did have an experience with my father that makes me believe in the afterlife.
In June 1987 my father, age 52, suffered a stroke which left him brain dead. After three days in a coma we had the life support system shut down and let him pass away. After about a week off I returned to work one Monday. That morning I turned around in the reception area of the office and saw my dad sitting in a chair smoking. I could swear that I actually saw the smoke rising from his cigarette. I kept seeing him there all the time. Since I thought I was really suffering from the loss of him I quit my job and moved home to "recover". I continued to see him at home. One time I opened the garage door and saw him standing there staring at me. Another time while talking to a friend on the phone I turned around and saw him sitting in the chair in the kitchen. I must have screamed an awful scream because the friend on the other end of the phone was at my house within minutes. This kept happening until December of that same year.
At that time my father's best friend came to our home with a long letter for us. It was handwritten on two full sheets of legal paper. He said that my father came to him in a dream and told him that he was trying to talk to us but he could tell that he was scaring me too much. So, he instructed the friend to get up out of bed and write down whatever he said. My dad visited his friend every couple of weeks until his letter was finished. After I read the letter I was extremely at peace and never saw my father again.
You see, my mom and brother both said that my dad came into their rooms the night he died and told them that everything would be all right and that he was very happy. I guess when he came to tell me the same thing I was too scared so he had to tell it through someone else.