I've written an addon called Serious Help In Timing.

It's basically a re-write of Face Mauler, but for Ret Paladins. You can setup your own priority rotation in the options menu, as well as a minimum amount of mana to continue consecrating, and the display frame will simply tell you which ability to use, which is coming up next, and if your Avenging Wrath is off of cooldown. Please let me know if you find any bugs or have any suggestions.

Currently, the only known "bug" is that it will recommend Exorcism without checking to see if the mob is undead. I didn't plan on releasing this before 3.1, so it isn't coded in. With 3.1 on the near horizon, I have no plans of adding it either. If you plan on using this for a fight like Malygos or Sarth before 3.1, then just change the Exorcism priority to double up whichever is above or below it, or just ignore the Exorcism recommendation and use whichever ability it recommends on the follow-up icon.

More information and screenshots can be found on the download page:

Serious Help In Timing : WoWInterface Downloads : Paladin

Serious Help In Timing - Addons - Curse