I can say from the things I have experienced in the past, I do believe in ghosts. That is part of the reason my wife and I started ghost hunting about 8 years ago. I will admit, you get a hell of a lot more nothing then getting something to happen. 99% of locations I investigated were not "haunted." Most of the paranormal events they experienced could be rationally explained and completely normal events.
As for Ghost Hunters and Ghost Adventures TV shows, I have met both groups of shows during my years of volunteering at the Mansfield Reformatory. I have talked to a lot of them about the show and what of it is faked. First off, most of the time they show up at a location, they do investigate them for a couple days if not longer. But the show is only filmed on one of the nights they are there. When the show isn't filming, they use their own equipment. The production companies won't let them air anything they capture on their own equipment. If nothing happens the nights they are in production, they will "recreate" the events they captured on their own. Personally, I think this is deception, and the main reason I don't watch the shows. They should at least explain that it is a recreation. Not all of the evidence they capture is not recreated. They have captured quite a lot on the production equipment. But there is a whole lot of editing and none of it is done by anyone in the paranormal field. And lastly, it is a TV show for entertainment. Ratings and money.
If you don't believe, that is fine with me. I was not a believe until I experienced some pretty crazy things years ago. I also don't believe any "evidence" that other people collect. I only believe evidence or experiences that I actually witnessed or captured.