When I'm washing I go: wheels, wheel wells, roof down to shoulder line and rinse, shoulder line down to waist line and rinse, then waist line down and rinse.
When I'm polishing/waxing I go: hood, entire drivers side, entire passenger side, trunk, roof, rear bumper, front bumper. Bumpers IMO are a PITA so they get done last. I should really get them out of the way first but I find if any part of the car is going to hold water it's the bumpers, so I give them maxium time to dry out.
Ben