And this folks, is why I remind my family - Just because it's soap, doesn't mean its clean..
I always wash from top down, with the exception of hair I do last. Since I practically have none (bit of shampoo every few days) I don't think this matters unless I have been shat on by a bird or something!
Neck/ears/face etc first (after a good pre-lather - see above, then a post-lather), then shoulders armpits, arms etc, then belly, balls and bum, down the legs to the ankles. Like someone else said here, I'm 190cm and at this point I am already uncomfortably prone! Feet are always dancing around in soapy water so they are fine, and I never got toe jam so it must be okay.