It's always a good idea to put down on paper your plans for the business, so that your team can build consensus around objectives and metrics. Make it as thick and wordy as you like (though show some restraint--over-modeling the future only wastes your time). I'm sure that Brad Feld's upcoming series on business plans will become the authoritative online reference for this kind of internal operating document.
But my advice is to never send a document like that to a VC.
Keep in mind that you are not alone--entrepreneurship is thriving around the world. In fact, we assess about 100 times as many investment opportunities as we fund, so as everyone knows, it's hard to get a VC's attention. It's not exactly true that all VC's are stupid (not exactly), but we do not have the luxury of an attention span. Drop a thick document on a VC, and it will, wrapped in good intentions, go straight to The Pile.