This has been around little while, but I figured I’d share it anyways. Healcrafter is a program that you can download that will import the Armory data for a specified priest, and will list useful information about their stats, healing longevity, the size of their heals, etc.
I know spreadsheets can do this, too. Healcrafter just displays things in a slightly cleaner fashion, and provides a fool-proof interface. It lets you tinker with your gear to see how changes or upgrades to it affect the size of your heals and your longevity. You can customize the length of a fight that you are interested in and the average percent of the time you spend in the five second rule.
Probably the coolest thing that Healcrafter does at the moment is with click it can show how your mana regen will increase in patch 2.4 (using the algorithm extracted from data collected on the test realms (note: that formula is inaccurate at intellect levels below 300; the formula will underestimate your regen)).
It still has some kinks in it, so take its current state as a another one of those really-good-works-in-progress types of things. It is certainly workable in its current form. There may be a few gems or enchants that it may not recognize, but those are the only kinks I have found so far.
And yes, this is tested as being virus-free. You are right to always be cautious when downloading stuff like this. Kapersky’s online anti-virus check confirmed that Healcrafter v188.8.131.52 is clean and safe.
Healcrafter is a Windows executable, and will likely not work on Macs, etc.
Healcrafter was made by Kevlar of Kilrogg-US can be downloaded from his website.
EDIT: There is already an updated version of Healcrafter out that fixes a few bugs. Kevlar is awesome and on top of it all! Also, the formula used for mana regen in 2.4 might actually be valid for all values of spirit and intellect greater than 1. :) I wish I could get on the PTRs to test it for myself.