Grab the Frostsavage set if you haven't already. It's starter/blue PVP gear with only a level 78 requirement, and it helps a bit until you get your honor gear.
The crafted purple/blue tailoring pieces are all BOE. For healing I am going with the Moonshroud gloves and robe (beware: it's fugly), the Aurora Slippers, Deep Frozen Cord, and Hat of Wintry Doom (if for no other reason than the cool name).
When I did this with my last priest I had Naxx-ready stats as soon as I hit 80 (this was back when Naxx was all there was), with quest rewards and a couple of rep items mixed in. I was Holy though; you might not need as much spirit and may want to look at the Spellweave robe and gloves for haste instead.
Edit: oh, and Titansteel Guardian if you haven't got anything better by then (some of the rep maces are better, IMO). It's boring and sucky, but it's a decent starter piece. I'm about to get my third one. :(
Edit again: I recommend picking up the Prison Manifest too. It drops off trash in heroic Violet Hold and there's usually a bunch at the AH. Good offhands are hard to come by and this one is pretty nice for a blue.
Edited, Sep 17th 2009 1:27pm by teacake