Ok, I understand the whole efficiency thing and how the more gears you have, the more often you can keep the engine in the sweet spot for whatever situation you are in. However, I would like to offer a point here. With a 6-speed, I almost feel like I can skip 3rd, and go to 4th, then skip 5th, and go to 6th. I would actually do this, except my owners manual says skipping gears is bad and will void my warranty. Anyway, a 7-speed just makes me think that the actual pleasure of driving a manual would start to rapidly decrease because you are always mashing at the gear box. Just my two cents. But who knows, I'm just a 3%er, so I'm probably weird and wired backwards.

EDIT: Also, I have owned cars with 3-speeds (auto and manual), and driving them, I never longed for another gear. Of course, I never drive on a track, but I doubt 99.997% of the population does either. Here's what a car tranny needs: a start/hill gear, acceleration gear, 45-55 cruising gear, 65+ cruising gear.