Good luck, I think you'll be better off w/ 4 rets, and a prot pally as your first team, but figuring out what you wanna play is 1/2 the fun. All the best.
Never take anyone's advice. Always follow your own vision and your own idea. There is always more value in your own idea.
That's ironic that you're offering advice, not to take anyone's advice, but I guess you didn't put 2 and 2 together, lol.
Anyways, his comment excluded, try out many things. but seek a lot of input, and make the best decision for you. I started with 3 dks, a resto pally, and tank. Listened to a lot of Boxer guys on here when I started, and I can honestly say my favorite team to farm HC's with is Dk tank, 3 rets, and a Disc priest. very fun.
If you want to PvP, I'd suggest looking into caster classes for that, I play 25 Shadow Priests, currently, I've got a Dru Team, and a shammy team, but the SP team is my favorite.
A pally team tends to fail outright when facing anything that can kite you. It's doable, but much harder.
I know a few guys that run boomkins, and no I don't fair to well against them, but not much can. And my focus is more PvE/PvP, more PvE though, I like doing raids my self, talk to the boomkin guys, they can't do that, and they are all PvP. So each to their own.
As far as Pallies go, run 1 Prot, and 4 ret, at max level, the divine storm will heal. You could consider taking 1-2 to max level and using them to power level your remaining team, and not level them together.
i myself am pretty new (about 1.5 month in), but no matter how much i learn, there seems to be always a ton more to learn haha. i use hotkeynet for the program, but regarding macros, in-game setups, etc. pls feel free to reach if you have any questions!