First off, please know that I will not and do not encourage you to spend your Emblems of Triumph on items from badge vendors with an item level lower than 232. This is because the additional 5-man dungeons added in patch 3.3 offer better or equal options to 226 or lower gear, and there is no sense in spending precious badges on gear you're going to get in heroics you're running anyway.
Second, know that this list will not concern itself with the best stat optimization for different specs. Min/maxing for heroic healing isn't exactly necessary or feasible, so just take what you can get to start. Delicate stat tuning can occur later when you are downing heroic bosses and sipping your elite, English breakfast tea like the classy priest you are.
Finally, if you're wondering what vendor items to buy first, the answer lies with what you already have on. Figure out what your worst piece of gear is and set out to upgrade it first. As you get more badges, just work your way up from worst to best; this way you'll get the most bang for your badge each time you purchase some gear. Of course, if you have personal preferences toward upgrading to something else first (say, a pretty robe over a hideous quest robe), feel free to stray from this advice.
When you first hit 80, you will likely not be able to queue for heroics in your quest gear. Don't waste your time toiling in normal dungeons, trying to find one upgrade at a time while getting no badges. Take some of that gold you made from questing and go to the auction house instead. Search for "Frostsavage" or "Black Duskweave" and you'll find various 187 item level gear. Players who are leveling tailoring sometimes make these lower-level items and post them on the auction house, so you should be able to find some cheap pieces. (Obviously, if you're already a tailor, you can make some upgrades yourself.) Don't buy a full set of gear off the auction house! Just buy one or two pieces and then trying queuing for a heroic dungeon. If you still get an error message telling you that your gear isn't good enough, buy another piece and repeat the process until you can queue. Alternatively, if you have a lot of gold to spare, look through the list below first and take note of the items that I suggest purchasing. A single piece of 245 gear is sometimes all you need to queue for your first random heroic dungeon.
- Cloak of the Fallen Cardinal -- Pit of Saron -- Oddly, there aren't too many cloak options available when you swear off old badge gear. Don't be dismayed, though; this one is at least easily farmable off the last boss of normal Pit of Saron, Scourgelord Tyrannus.
- Cloak of Displacement -- Dropped BoE -- You can find this BoE cloak from Trial of the Crusader on the auction house if you're lucky. It drops some stats into hit, so it's not perfectly optimizied for healing, but if you have the gold to spare this is quite a significant step above Cloak of the Fallen Cardinal.
- Velen's Robe of Conquest (Zabra's Robe of Conquest) -- 50 Emblems of Triumph -- This is an obvious upgrade choice -- so obvious that there isn't much to say about it. I personally always upgrade my robes first when I hit 80, just to get out of the icky-looking quest robes.
- Merlin's Robe or Royal Moonshroud Robe -- Crafted BoE -- If you don't want the tier 9 bonuses and have some time or gold to spare, these crafted robes provide better stats than the 232 tier 9. These should be more affordable with the recent changes to tailoring cooldown cloth and frozen orbs, so it might be worth it to you gather up the mats and have one of these two robes made.
- Prelate's Snowshoes -- Heroic Pit of Saron -- There aren't a good pair of boots you can purchase with badges, but you can pick up these boots of the last boss of heroic Pit of Saron, Scourgelord Tyrannus. Thank you to Dirgo for informing me of their existence!
- Ice-Steeped Sandals -- Pit of Saron -- These boots drop off of the first boss in normal Pit of Saron, Forgemaster Garfrost. They're not the best option, but while you're farming your cloak, you can pick these up if they drop.
- Sandals of Consecration -- Crafted BoE -- These are actually a pretty sound investment if you have the gold to spare. There aren't many boot upgrades in Icecrown Citadel, so these crafted boots might be something you'd end up having made anyway.
- Band of the Invoker -- 35 Emblems of Triumph -- For your first finger slot, this ring offers a nice selection of stats.
- Heartmender Circle -- 35 Emblems of Triumph -- For the other slot, you can pick up this ring with MP5.
- Velen's Gloves of Conquest (Zabra's Gloves of Conquest) -- 30 Emblems of Triumph -- These gloves will likely be the easiest option you have to upgrade from your quest gear.
- Suspiciously Soft Gloves -- Heroic Halls of Reflection -- If you 1.) don't want tier bonuses and 2.) don't want to spend badges, then you can try hunting down these gloves from heroic Halls of Reflection. The stats are about on par with the tier, but they're not as good as the tier, since they lack a gem socket.
- Helm of Clouded Sight (Hood of Clouded Sight) -- 75 Emblems of Triumph -- This non-tier helm is my first choice to pick over the 232 tier 9 helm. The stats are better, and I consider a yellow gem slot more favorable than the blue socket in the tier.
- Velen's Cowl of Conquest (Zabra's Cow of Conquest) -- 50 Emblems of Triumph -- This is the 232 tier 9 helm for reference. If you end up picking up a non-tier piece in one of your other main items slots, this is an option for nabbing the tier bonuses.
- Arcane Loops of Anger -- Heroic Forge of Souls -- You won't have a good vendor option for your neck slot, so heroic Forge of Souls is going to be the place to look for an upgrade. This neck drops from the Devourer of Souls, the second boss.
- Love's Prisoner -- Heroic Forge of Souls -- As I said above, there is no vendor neck option I would recommend. This neck, also from heroic Forge of Souls, drops off the first boss, Bronjahm.
- Blood Queen's Crimson Choker -- Dropped BoE -- For the affluent Azerothian, this BoE neck from Icecrown Citadel will be an amazing upgrade.
- Shriveled Heart -- Heroic Halls of Reflection -- You can pair this with your Pit of Saron dagger to get the best, pre-raid weapons available. You can also link it in chat for the occasional bizarre or morbid joke. Not that I do things like that.
- Pauldrons of Revered Mortality (Mantle of Revered Mortality) -- 45 Emblems of Triumph -- Before you spend your badges on this, decide if you want to make use of the tier 9 four-piece bonus. If you do want the bonus, don't buy these shoulders. If you don't want the bonus, these shoulders will provide you better stat upgrades than 232 tier 9.
- Velen's Shoulderpads of Conquest (Zabra's Shoulderpads of Conquest) -- 30 Emblems of Triumph -- This is what you want to grab if you don't plan on using your tier 9 four-piece bonus.
- Stiffened Corpse Shoulderpads -- Dropped BoE -- Here is another money bags option you can look for on the auction house. Should you be able to afford this and more, I wouldn't pay mind to the set bonuses on the 232 tier 9 pieces.
- Ephemeral Snowflake -- Heroic Halls of Reflection -- While this is far from being the best trinket you'll ever find, it's certainly a great start for a regen trinket. The use effect is rather "meh," but you could treat it as a miniature "oh shit" button to speed up some casts in a bad moment. This trinket drops off Marwyn, the second boss in Halls of Reflection.
- Tears of the Vanquished -- Trial of the Champion -- This trinket is a decent option to farm out of normal Trial of the Champion. It should be easy to find a group to farm this trinket, since the other 200 level trinkets available in the dungeon are highly sought after by DPS classes.
- Je'Tze's Bell -- Dropped BoE -- This is another one of those items I actually recommend saving your gold for, if you want a mana regen trinket.There are usually a couple of these trinkets available on the auction house, and it will set you back about 800 to 1,300 gold. I wouldn't spend any more than that.
- Talisman of Resurgence -- 50 Emblems of Triumph -- I don't care much for this trinket, but it is an option. The base intellect may help you out early on with pumping up your mana pool, but ultimately you'll want to find a more active regen trinket. The trinket's use effect isn't bad, but it will be up to you to utilize.
- Braid of Salt and Fire -- Heroic Pit of Saron -- As I said earlier, don't spend your badges on gear that has an item level lower than 232. This will unfortunately limit your options for certain gear slots, and the waist slot is one of them. This belt from heroic Pit of Saron (off the second boss, Ick) is the solution, although it may require some time or luck to acquire, seeing as it comes from a heroic dungeon.
- Strip of Remorse -- Heroic Halls of Reflection -- This belt is an alternative upgrade to the Braid of Salt and Fire. You'll have to run heroics to get it, as well; it drops from the chest after you finish heroic Halls of Reflection.
- Cord of the White Dawn -- Crafted BoE -- This is the one case where I will list an item below 232 item level. The reason why is because with the cloth cooldown changes, this belt is significantly cheaper to craft than it once was, so if you have the resources to have it made you might as well. With the potential to attach three gems (two sockets, plus one from belt buckle enchant) you can get a tiny bit ahead of the spellpower on the two 232 belts I listed above. Weigh your costs though.
- Brimstone Igniter -- 25 Emblems of Triumph -- Even though this wand has hit on it, it's cheap and easy to attain and will likely provide a decent spellpower upgrade to whatever you've got on.
- Soulsplinter -- Heroic Halls of Reflection -- If you don't like the idea of spending your badges on hit gear and you are able to queue for heroic Halls of Reflection, this wand drops off the first boss, Falric.
- Nightmare Ender -- Dropped BoE-- If you have deep pockets, keep your eyes on the auction house for this wand from Icecrown Citadel.
- Surgeon's Needle -- Heroic Pit of Saron -- This is the weapon you'll want to hunt down. Its the best weapon you'll find without going into a raid, and it beats the Trial of the Champion weapons quite a bit on stats. This drops off the first boss of heroic Pit of Saron.
- Bejeweled Wizards Bracers or Royal Moonshroud Bracers -- Crafted BoE -- Unlike most BoE items, the crafted 245 bracers are a bit more affordable to have crafted, especially with the recent changes to tailoring cloth cooldowns and frozen orbs. I would recommend putting in the time or gold to getting one of these bracers for yourself. As a note, the Royal Moonshroud Bracers tend to be more affordable.
- Wristguards of Subterranean Moss -- Pit of Saron -- The reason I recommend the crafted bracers so much is because these are the next, non-hit bracers you'll find without raiding. Fortunately, they drop from normal Pit of Saron (off the second boss, Ick), so you can farm them until they drop.
- Bracer of Worn Molars -- Heroic Halls of Reflection -- These bracers have hit on them, but they're a better upgrade in raw stats when compared to the Wristguards of Subterranean Moss. If you should come across them, you might as well bite the bullet and take the hit.
There! This list should keep you busy for a while. If you get all the gear above, you'll be more than ready to dive into tier 9 raids like Trial of the Crusader or Onyxia's Lair. You should be able to squeeze into Vault of Archevon groups prior to having all this gear too, so be sure to check those out; you might get lucky and get some better upgrades than what is listed here.
Don't forget to gem or enchant your gear!
* Shadow priests represent the highest number of victims in lethal pedestrian/Elekk-related accidents.
Want to find more great tips for carrying out your priestly duties? Spiritual Guidance has you covered with all there is to know. Check out Holy 101 or Disc 101 for an introduction to healing as a priest, or assess yourself for advice on how to improve yourself as a healer and raider.