Jim, the local differences are interesting. The most common placement, in my experience, is 4', just over the top of the machine. The exception being the finely appointed laundry room in more expensive "designer" settings where the plug is desired out of sight.most prefer it at about 3ft so they dont see it.
Same here Al. It's what I'm used to seeing, and decorating concerns aside I always felt it should be readily accessible.The most common placement, in my experience, is 4', just over the top of the machine.