On Mynt’s suggestion I went ahead and downloaded/installed Jim’s Cooldown Pulse.
When an ability’s cooldown ends, Jim’s Cooldown Pulse shows the icon for that ability at a position/size on the screen that you’ve specified. It also plays a heartbeat sound to draw your attention. This allows you to keep your eyes in the center of the screen instead of staring at buttons and their cooldowns.
In the picture above Jim’s Cooldown Pulse icon is above my hud. It’s telling me that Judgement is now available again.
Yes, I’m fiddling with my UI again. Doing the “State of the UI” made me examine my UI more closely and I found a few things I wanted changed. Work in progress.
[Edited to add:]
See Jim’s Cooldown Pulse in action here: http://www.warcraftmovies.com/movieview.php?id=48121. Seems to be a must-have addon for PVP.