My first bike was a 73 Honda CB450. I rebuilt the engine on it and it was pretty torquey. I think the fastest I got it was 90 going downhill, but it could accelerate pretty quick. Never did have a helmet to ride it though. Had a pair of goggles...
I always ride with boots, jeans, leather jacket, and a helmet now. Sometimes the leather gets hot and sometimes (rarely), I miss the wind in my hair, but I'd much rather have a noggin intact. Plus, as smooth said, I go too fast. 70+ mph on the 1200 is easy speed to get to...
I've been thinking of getting one of thse synthetic jackets that breath and don't flap around so much. (sorry, off topic)
I really don't find the helmet inconvenient when riding. Sometimes it's a pain to lug around when I'm off the bike but it sure is nice when that big ass bug goes splat on my face shield at highway speed. I just don't see any good reason not to wear one, and the "cool" factor doesn't even come close.