They are like fingerprints; no two are alike, even within the same organization. One further point, opinions about what makes a good finished product are like noses_everybody has one. The ones that work and prove to be executable are the best. With this in mind, let me offer my views about business plans at a macro level having written a sizeable number of plans for internal and external applications. One other point, a business plan can build a team quicker than any formal team building activity.
The "Accidental Entrepreneur" Plan: Believe it or not, it happens quite often. An impulse, a hobby, or a passing notion turns into a business without warning. One day you're handing your extra back_yard tomatoes or homemade cake to the neighbors, and before you know it you're filling out the forms for a booth at the local farmer's market. Perhaps you create a unique bit of hand_crafted jewelry and wear it to school or work, and then find your phone flooded with messages like, "Where can I get one?" and "I'll pay you to make one for me."