Gratz on your first heal!!
As far as lvling, I went holy at 60 and haven't looked back. I have changed my holy build up since I hit 68, but eh.
I personally don't like Zanger. I actually dreaded going there and wanted to find a way around it so that was the main reason I specd holy (and it was what I was going to do at 70 anyway). All I did was instances up to lvl 66, and WOW!! I got the best blues to heal, I never hit a quest and always had a group within 5 min of logging on to run (seems to be a shortage on healers on Bolderfist). Everyone's looking for a healer.
I went with
this build till 68 and was impressed. Never had a problem healing, even a so-so group through Black Morass, and when I decided to go and start questing again I was impressed at how well a holy priest did solo. No down time, in a fix? shield, renew, and start smiting again. The other upside I'm finding as I get close to 70 (almost half way now) is that all these quests that I left behind are going to just be easy money and rep. And questing in Blade's Edge Mts is pretty easy as a lvl 69 working against lvl 63-64 mobs.
I loved shadow. Still collecting gear for it (though I haven't found a reason to go back yet). But lvling holy the way I did was easy. Oh yeah, and as an enchanter, running instances was choice. So many blues and greens to DE.
GL.