I've been playing the Priest more and more and enjoying the versatility that the class brings as compared to the Druid. I'm still rocking the cow every now and then, but I think it's more for sentimental reasons than actual enjoyment. I am probably still going to go after that "What a Long, Strange Trip It's Been" meta achievement on the Druid since I've already slaved away for Elder and The Love Fool titles, but that's more of a matter of time than anything else.
As I'm going through and learning the in's and out's of PvP with this class, the absolute hardest thing I find is managing my global cooldowns while paying attention to my positioning AND making sure I'm understanding the flow of the match. I find that my GCD can't come back up fast enough and I'm either always missing some key ability, out of position, or just a fraction of a second too slow.
To that end, I've made a few macros that have saved me from going crazy. If there's anything that's saved me a few seconds it's macroing important defensive abilities to auto target myself or my partner. It's to the point that I have all of my Character macro's filled up and I'm starting to edge into the General Macro slots. I've even pulled my Shadow macros (Silence, Focus Silence) to ensure that I have enough slots.
It's really helped a ton.
Don't know where to get good macros? www.arenajunkies.com and www.elitistjerks.com are two good resources. There are also a ton of 'how to make a macro' guides on the WoW forums... if you can stand them.
3 other quick points:
1: Beating DK/Paladin is so satisfying
2: Get a mod like Spell Alerter or Miks or Power Auras and make a big ass warning show up whenever Divine Shield has been used. It's great for popping bubbles wherever you go!
3: Anyone else's raiding guild going through a slow time? 3.1 can't get here fast enough imo.