I do most of my thinking while trying to fall asleep. Stuff goes round and round in my head and it's pretty awful. I've been having trouble falling asleep lately..
But, I can never say where my mind does its best thinking. I've got so many things running through my mind that I could tell myself I should figure something out and without even noticing it, I'll be thinking about some random unimportant thing.
But, I do like to do my thinking on the toilet, in the shower, or when I'm out walking. But I hardly do any thinking when I'm walking while listening to music, which I like am 99% of the time. But usually when I go out for a walk, especially in the winter and it's snowing, is when I get the most head-clearing done.
During the spring/summer, I'll go to a park and lie there for hours with my music, or without. That's so relaxing and spiritual.
I want summer. :(