Hmm, I always make my bed.
What can I say...I was raised by an ISTJ mother who is extremely rigid when it comes to these sorts of things, and 'manners', and appearances, and all of that, and it has rubbed off on me. :-)
I like how it looks. And I like lying on top of it during the day without any sheets or covers in the way.
As to 'most people'...hmm...I would imagine it's about half and half.