I live in the northern hemisphere, and wish more maps supported "South up." Maybe I'm weird, but in my mental map I expect the light (the sun) to be at the top of the page.
Heh, you say that as if I didn't know! ;)
I'm sure you've noticed that in computer UIs, all the "3D" effects are based on the sun being at the top. Same with geography -- it's easier for me to visualize the terrain if the sun is at the top. That means South-up in the northern hemisphere, and North-up in the southern hemisphere.
Always fun to watch that West Wing clip.