I define a power user as someone who does a multitude of things on a computer that are unrelated and stress the computer, so no, I wouldn't call them power users.
They do a direct, specified task.
Alienware = kids that have lots of money and like to play games, but don't goto lan parties (cause if they did I'd beat em up lol).
Apple = someone who either is an apple freak, a dedicated "editor" of something, or someone who just doesn't want to bother with "stupid windows that crashes every 5 seconds".