Josh Bernoff has a great post asking developers to stop referring to people as "users:"
"I will think of people who use technology as people, customers, and friends. I won't use them, and they won't use me."
I know it sounds trivial, but I've also wrestled with what to call people who use my software. Out of habit I'll often refer to them as "users," but I've been trying to use the word "customers" instead. Something about the word "users" implies a certain lack of power, whereas "customers" have clout. And it helps developers to remember that their customers are in charge.