Yes, BTMRR is a totally different ride in the dark! It just seems faster and crazier and all around better!!! I always try to hit that one when it's dark.
I really love walking around the parks at night, especially MK--it just seems so pretty at night. I also love walking around World Showcase at night...sometimes we will literally spend hours just strolling around WS, drinking beers and talking, and not really 'doing' anything else. It's really wonderful!!!!!