This list should give you an indication on which items you are after.
NB: Do note that not all if these items are in game at the moment and some items will gets better stats in later patch.Pre-RaidHead:Spellweaver's Turban - General Drakkisath, UBRS
Neck:Dark Advisor's Pendant - Vectus, Scholo
Shoulder:Eternal Shoulderguards of Shadow Wrath (+30 spellpower green BoE) or Felcloth Shoulders - Tailor BoE
Cape:Archivist Cape of Shadow Wrath - Archivist Galford, Stratholme or Spritecaster Cape - Houndmaster Grebmar, BRD
Chest:Bloodvine Chest - Tailor BoE
Wrists:Rockfury Bracers - Silithus Quests
Mainhand Weapon(s):Blade of the New Moon - Immol'Thar, DM West or Scepter of the Unholy - Baron Rivendare, Strat UD
Offhand(s):Tome of Shadow Force - AV Exalted
Wand:Skul's Ghastly Touch - Skul, Strat Living
Gloves:Felcloth Gloves - Tailor BoE
Waist:Ban'Thok Sash - Arena, BRD
Legs:Bloodvine Leggings - Tailor BoE
Feet:Maleki's Footwraps - Maleki the Pallid, Scholomance
Rings:Maiden's Circle - BoE world drop
Maiden's Circle - BoE world drop or Don Mauricio's Band of Domination - Darkmaster Gandling, Scholomance
Trinkets:Briarwood Reed - Jed Runewatcher, UBRS
Draconic Infused Emblem (short or medium fights)- General Drakkisath, UBRS
Mindtap Talisman (long fights)- Magister Kalendris, DM West
BIS Pre-AQ GearHead:Spellweaver's Turban - General Drakkisath, UBRS
Neck:Choker of the Fire Lord - Ragnaros, MC
Shoulder:Mantle of the Blackwing Cabal - Razorgore, BWL
Cape:Cloak of the Brood Lord - Nefarian, BWL
Chest:Bloodvine Chest - Tailor BoE
Wrists:Rockfury Bracers - Silithus Quests
Mainhand Weapon:Lok'amir il Romathis - Nefarian, BWL
Offhand:Tome of Shadow Force - AV Exalted
Wand:Touch of Chaos - Hakkar, ZG
Gloves:Ebony Flame Gloves - Ebonroc, BWL
Waist:Firemaw's Clutch - Firemaw, BWL
Legs:Fel Infused Leggings - Kazzak, World Boss
Feet:Snowblind Shoes - Azuregos, World Boss
Rings:Band of Dark Dominion - Trash Drop, BWL
Ring of Spell Power (short fights) - Harbinger, Lucifron, Gehennas, Shazzrah; MC
Ring of Blackrock (long fights) - Ebonroc, Flamegore, or Firemaw; BWL
Trinkets:Neltharion's Tear - Nefarian, BWL
Talisman of Ephemeral Power (medium fights) - Golemagg, Magmadar, Garr, Baron; MC
Zandalarian Hero Charm (short fights or fights with lots of dots) - Hakkar, ZG
Shard of the Scale (longest fights) - Onyxia
Source:
http://www.wow-one.com/forum/topic/88243-bunnehs-raiding-shadowpriest-guide/ - UPDATED 10/11/15