I've spent huge amounts of time on my current project trying to decide whether things should be called "Services" or "Servers", and whether the message we send when someone enters a room should be "Enters" or "Entered".
I was talking to someone some months ago who characterized all of the "interesting" problems into two groups: overconstrained and underconstrained. I'm much better at the overconstrained ones. It's the arbitrary decisions that get me. Someone needs to give me an Executive Decision Maker for the holidays.