I, too, think that away message systems CAN be annoying. But that's more of the user than the away system itself.
For example, I have an away system installed that I will use occassionally, but if it repeats my away in the rooms, it's hours apart and not so often that in a 'dead' room, you have a screen full of away's after only a few hours.
And I tend to not change my nick either - because that way, people never know if I'm watching or not, and a room that I watch requires strict rule enforcement. teehee