There's no reason to make yourself sweat if you don't have to. Humor has not only worked for me as a presenter, but on me as a prospective buyer. And I've since bought twelve more acres from him. Never forget that people come to presentations for entertainment. They can get information from books, computers, movies and magazines.
People never attend a presentation just for the facts.
They really come to see you in action. Maybe they've heard listening to you is worth their time. Maybe they think your showmanship is a welcome break from doing hard work in the office. A glimmer of light in a sea of darkness. Props, jokes, stories, acting -what a great way to get the necessary scoop.