I got wrecked in WSG (vanilla, same premade vs premade so many times every day) by a shadow priest on my hunter.... So I rerolled priest but ended up hating shadow.. went some trispec optimized for WSG and helped our team grind 4 people to rank14 (myself only reached 12 due to having a job and 10h play/day wasnt enough to rank14).
After that we started getting wrecked again due to opponents cleared BWL and started Naxx (my team only focused on PVP), so we had to bite the bullet and start raiding to be competitive in PVP! .. and since then it's been a holy or disc priest for me (except Wrath when pally tanking).. eventually stopped raiding in late Cata and never picked that up since.
Now I'm unsubbed since ages and waiting for Blizzard to do their magic on the disc-priest, making me wanna come back and have FUN again. If not.. yeah there's always Diablo 3!