- Elementalist Gloves of Shadow Wrath. Yet another of Shadow Wrath green. Remember, I would advise against equipping too many of these, regardless of how good they are in-slot.
- Tempest's Touch (Caverns of Time quest).
- Gloves of the Deadwatcher (Shirrak, Heroic Auchenai Crypts )
Major Spellpower is, quite expensive, but other BC enchants are not worth bothering with. I'd say put it on any of the above. The old-world enchant Shadow Power is equivalent for you, if that's more convenient.
- Belt of Blasting (BoE tailoring, ~1500g). I've had some trouble finding this, but it is super-nice (if pretty expensive.)
- Archmage Belt of Shadow Wrath
- Glyph-Lined Sash (Nexus-Prince Shaffar, Heroic Mana-Tombs)
- You should almost certainly go for Spellstrike Pants (unless you're swimming in badges, in which case get the 100 BoJ Legwraps of Sweltering Flame)
- If you really don't want to (though I can't imagine why you wouldn't, given that you don't even need to be a tailor), Chimaerahide Leggings of Shadow Wrath or Elementalist Leggings of Shadow Wrath can fill in for you. But do yourself a favor and just go with Spellstrike.
- Frozen Shadoweave Boots. Strictly better than anything pre T5.
- Shattrath Jumpers (Shadow Labyrinth quest). Anyone should be able to get either these or the FSW boots.
Vitality, though it's not a big deal. Probably put it on either of the above, but it's a higher priority to enchant other slots and get yourself gemmed out.
Unlike most classes, you may find yourself not equipping the Violet Signet until Revered, Exalted, or ever, depending on what you already have; it has a fair amount of spell crit, which is sub-par for you. - Ashyen's Gift (Cenarion Expedition exalted). Simply awesome. - Seal of the Exorcist is quite strong, even though the resil does nothing for you in raids. Besides, what else are you going to spend your Spirit Shards on? - Band of Arcane Alacrity (Vexallus, Magister's Terrace). I didn't mention spell haste when going over stats, because it's hard to find pre-T6, but make no mistake, it's quite nice. - Seer's Signet (Scryer exalted) - Cobalt Band of Tyrigosa (Nexus-Prince Shaffer, heroic Mana-Tombs)
Ring enchants, of course, are enchanter-only; if available, you'll want Spellpower.
- TIIIMBALLLL'S! (Delrissa, Heroic Magister's Terrace)
- Darkmoon Card: Crusade (reward from the Darkmoon Faire for a Blessings deck). Expensive, but worth it.
- Icon of the Silver Crescent (41 BoJ).
- Sorcerer's Alchemist Stone. If you're an alchemist, this thing is hot stuff.
- Quagmirran's Eye (Quagmirran, Heroic Slave Pens).
- Scryer's Bloodgem (Scryers revered)
- Arcanist's Stone (Epoch Hunter, heroic Old Hillsbrad)
- Ancient Crystal Talisman/Glowing Crystal Insignia (Zangarmarsh quest)
Alright, that ought to be enough trinkets; use the best two of those that you can get your hands on.
A main-hand, along with an off-hand, is almost certainly going to be better than a staff.
- Cudgel of Consecration (Kael'thas, Heroic Magister's Terrace). You may have to fight a Paladin tank, or other casters, for it, but it is a thoroughly excellent weapon (better than anything pre-T5)
- Merciless Gladiator's Gavel/Spellblade. When season 4 goes live in two weeks, this season 2 stuff will be available for honor. Nobody knows exactly how much honor, but I'm guessing it will be on par with what the season 1 stuff is currently selling for now (25,200 honor and 20 EotS marks). There's no difference between Gavel and Spellblade except appearance, so pick the one you think looks better. If you really can't decide, pick the Gavel; it has a higher maximum durability.
- Eternium Runed Blade (BoE blacksmithing, ~1500g)
- Gavel of Unearthed Secrets (Lower City exalted)
- Sky Breaker (Avatar of the Martyred, Heroic Auchenai Crypts)
Major Spellpower! We love spellpower here at Shadow Priest Central. Soulfrost is actually better, but it's shockingly expensive. I would put it on the Cudgel of Consecration or a Merciless Gladiator's weapon, but not anything less.
- Orb of the Soul Eater (25 BoJ). Fetish of the Primal Gods is actually very slightly better, but the difference is tiny, and it costs 10 badges more. The Orb is a steal for only 25 badges. This will last you a very long time.
- Draenei Crystal Rod of Shadow Wrath
- Carved Witch Doctor's Stick (25 BoJ). Best 25 badges you can spend, next to the offhand. Get it now. There's little better in the entire game.
- Flawless Wand of Shadow Wrath
- Illidari Rod of Discpline (from yet another SMV quest)
But seriously, just get the Badge one. This goes for the offhand, too.
You've probably heard this before, but let me tell you again: ignore the socket bonuses. In the vast majority of cases, you're just going to want to put Runed gems in everything; it won't be worth socketing yellow or even (shudder) blue gems to get +2 int or whatever. Obviously there are a few exceptions, so look at the socket bonus, but most of the time just toss in the red gems.
I'd advise putting Living Rubies in most of the stuff on this list, though Blood Garnets will suffice for the lower-quality items. Do not leave sockets open; you're just throwing away stats if you do that. Put in Runed Tourmalines if you really have to.
And there you have it: some lovely and relatively easy to obtain gear for entering the halls of Karazhan in Shadowform. You can get by with less, especially if your raid is well-geared and/or well-played, but I think these items are good to aim for. Have fun, and remember to keep Vampiric Touch up at all times.
In closing, I would like to give a massive shout-out to ShadowPriest.com, the best place I've found for Shadow information. The "Best casual gear available" list especially contains much of the information on which this guide is based. The Elitist Jerks thread "Shadow Priest 101" is also a must-read.