I've said it before, and I'll say it again: Gearing in Cataclysm is a no-brainer. Blizzard finally gets the needs of different classes and seems to be making gear that we actually want. Spirit plus haste gear is all over the place. So is mastery plus haste gear. And since almost everything worth getting has red sockets, we don't even need to do the math on what gem to use. And even with the "wrong" gear, reforging can make it almost as good as a best in slot.
There's one place where gearing up is still somewhat of a challenge, and that's the trinket slot. Instead of flat secondary stats, trinkets typically rely on procs with unspoken internal cooldowns and hard-to-theorycraft bonus damage.
When two numbers follow the name of a trinket, the first represents the pseudopower of the regular version; the second represents the pseudopower of the heroic version. When three numbers follow, the first represents the Raid Finder version; the second, the regular; and the third represents the pseudopower of the heroic version. Pseudopower numbers are calculated using the same SimulationCraft numbers that Mr. Robot uses.
The best of the rest
Due to space constraints, I can't list every single trinket available. Still, there are a few odd older trinkets that can at least hold their own against those listed below:
Dawn Moore's list of the top trinkets for healing priests.)
Top 7 shadow priest trinkets
7. Necromantic Focus (570 / 644) The Necromantic Focus has been available to shadow priests since patch 4.2 launched; it drops from Baleroc in the Firelands raid. But even with new trinkets being available in patch 4.3 via valor points and 5-mans, the Necromantic Focus still holds up well.
Trinkets like these are terrible for trash pulls with slow-moving tanks -- the Soul Fragment buff drops off after 10 seconds. But for most raid fights where you're steadily DPSing a target, this trinket makes for a fairly reliable, static mastery buff.
6. Darkmoon Card: Volcano (591) I've had and held on to Darkmoon Card: Volcano since the early days of the Cataclysm expansion. A lot of it was bad luck in Firelands and Dragon Soul rolls. The other half of the equation? DMC: Volcano is simply a terrific trinket.
It doesn't hold the BiS honors it once did, but the intellect proc still makes this a terrific trinket. Just be sure you reforge the mastery to haste.
5. Foul Gift of the Demon Lord (628) For the casual shadow priest, one of the most exciting gear additions of patch 4.3 was the Foul Gift of the Demon Lord. Until then, for a shadow priest who didn't have a regular raiding team, trinket options were few and far between. No longer -- shadow priests now have a great trinket waiting for them in the Well of Eternity.
The trinket has a static 383 intellect and a 20-second mastery proc that you'll see once every 45 seconds or so. There's also an on-use aspect to the trinket, but it's mostly just for show. If you do get this trinket, just be sure you understand how to game mastery and get the most out of it.
This trinket procs off of DoTs, and given how fast and furious damage numbers fly around a shadow priest, you can imagine that Electrical Charges build quickly. The true pseudopower of those Charges is difficult to calculate, but using SimulationCraft, we can estimate that the regular version's proc is equivalent somewhere around 225 intellect; the heroic version is wroth somewhere around 250.
You gain an Electrical Charge each time you cause a damaging spell critical strike, granting a chance to fire a Lightning Bolt for 985 to 1,266 damage per Electrical Charge accumulated. You cannot have more than 10 Electrical Charges and cannot gain one more often than once every 2.5 seconds.
3. Insignia of the Corrupted Mind (647 / 730 / 825) The Insignia of the Corrupted Mind, a drop off of Yor'sahj in the Siege on Wyrmrest half of the Dragon Soul raid, is a pretty traditional trinket. It offers a base amount of intellect (406 / 458 / 517) and has a haste proc called Velocity that offers 2,573 / 2,904 / 3,278 haste for 20 seconds. The internal cooldown appears to be around 115 to 120 seconds, so you can count on the buff having uptime of at least 16.7%.
The math is compelling. This may not be the BiS trinket for shadow priests, but for those of us who are still holding on to that darned Darkmoon Card: Volcano, it's a solid get.
2. Will of the Unbinding (~780 / ~880 / ~990) If you're looking for a simple but powerful trinket without the BS, Will of Unbinding is it. It drops off of Spine of Deathwing in the Fall of Deathwing half of Dragon Soul.
The proc of Will of Unbinding works very similarly to that of the Necromantic Focus, except that Will's proc offers intellect, not mastery. Over the course of a raid fight where you're constantly DPSing, you'll quickly build to enjoy a static 880 intellect buff (780 intellect for the Raid Finder version; 990 for heroic).
1. Cunning of the Cruel (? / ? / ?) Ladies and gentlemen, meet Cunning of the Cruel, your best-in-slot trinket. So what's the selling point here? The intellect is great, of course -- even the i384 version offers a whopping 406 points of it. But the real star of the show is the proc:
The internal cooldown on the trinket seems to be around 30 seconds, and yeah, your current target gets damaged too. And before you ask, yeah, it does proc off DoTs, meaning shadow priests seldom have to wait long after that 30-second timer expires.
Equip: Your damage dealing spells have a chance to trigger a Shadowbolt Volley, dealing 7,495 to 11,242 damage to all enemies within 10 yards of your current target.
How it performs in fights is obviously dependent on how many adds you see -- the more, the better. In fights like Yor'sahj, where you have occasion to fight multiple adds at once; Warmaster Blackhorn, where the fight is the adds; and Deathwing, the Shadowbolt Volley proc is absolutely luscious. But even in single-target fights like Morchok, this trinket holds its own. And obviously, it's terrific for trash.
There aren't any truly solid pseudopower numbers on this hot little trinket because it's so fight-dependent. And opinion as to whether or not this is BiS depends on who you ask. Howtopriest.com says yes; Kilee at Shadowpriest.com says no. Thankfully, though, the question is largely moot -- if this isn't your #1 trinket, it's going to be your #2.
Are you more interested in watching health bars go down than watching them bounce back up? We've got more for shadow priests, from Shadow Priest 101 to a list of every monster worth mind controlling and strategies for raiding Blackwing Descent.