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.
At this point, you may be tempted to skip writing a business plan altogether, viewing it as an unnecessary exercise in jumping_through_the_hoops, suggested by some old business professor who probably never held down a "real" job anyway. Maybe it's okay as an assignment for an MBA class, but it would be just too confining and irrelevant for today's fast_paced business environment. Anyway, you're ready! You've thought about this business venture for a long time and talked it over with friends and everybody agrees it's a great idea. Best to strike while the iron is hot!