Used it for years — loved the waypoint lines that it would make on your map (tracking routes from one quest to another), and the waypoint arrow at the top of the screen. Now built-in to WoW, and there’s no need for it anymore. Even the dev is leaving it.
Also built-in to WoW now, although the implementation isn’t as good as the addon’s — you can’t look at someone else and zoom into them, for instance. This was one of those addons that, while being a mild modification to the game UI, you still found yourself using it nearly every single time you logged on.
Hopefully, there won’t be more to come! :P
One more: PerformanceFu. Hasn’t updated in about 2 years. Liked it because it would let you see some cool stats right from your FuBar — I’ve noticed that his seems to be built-in to the standard WoW button menu now. So long!