The key is definately maximizing profit/pint. A taproom would give the highest return, though you have to pay for the space, furnish it, and probably pay someone to sell your beer too (assuming you'll be too busy brewing). Seems many nano's bottle in bombers, which bring the highest price/oz.
The successful ones probably have unique situations that make it work, such as already owning the building the brewery is in and/or buying equipment with disposable income (or already owning a massive homebrew system) rather than financing and truly incorporating those costs into the business.