At one point I had a second priest as shadow, and got him into his 20's. I lost interest in that and deleted him. Every so often another class will peak my interest and I'll give it a go. Right now I am gearing up my druid healer and comparing play style with the priest.
This one is horde and on another server. I originally Thought of making this priest Shadow/Holy, but right not it's shadow disc because I like disc too much and it makes healing in BG's much easier.
I've not exactly got two priests capped, but my second one is at level 64. Reason I decided I needed one more is because the 64 one was my old main - a Dwarf priest on another server. Seeing as I'm now horde on my current server and I wanted to play a priest in end-game, I figured I'd had to create a new one. This was before the gender/race transfers were in sight, obviously.
Gratz, I only have one priest but two level 80 hunters. Although my second hunter was born out of a desire to move servers and factions (before the lame cheaters nowadays! (which I totally didn't use for my shaman, she just magically changed from a female draenei to a male troll just like he changed servers and my bank account got billed )
I have two at capped (same faction and server)... I had level two to 70 long before Blizzard even hinted at allowing two specs... So Amallthia is my main hardcore raider and Melefacent has now become my plant picking, rock hacking slave! ^_^
I have a lvl 28 draenei priest who was created prior to my switch to the darkside. Now her main function is moving goods through the neutral auction houses and looking very sexy.
I plan to lvl a goblin priest for ***** and giggles :) same server as well that way I can use my husband's DK to run her through instances.