Priest

Major

• Glyph of ShadowLevel 20Your critical strikes grant you spell power based on your Spirit: always keep it.
• Glyph of Mind FlayLevel 20Shadow Word: Pain stays up all fight: 10% free damage for Mind Flay.
• Glyph of DispersionLevel 60Dispersion comes back much sooner, to regain mana or absorb an attack.

Minor

• Glyph of ShadowfiendLevel 66Get mana back if your Shadowfiend dies before it expires.
• Glyph of LevitateLevel 34No more feathers to carry for Levitate.
• Glyph of FortitudeLevel 15Less mana spent buffing the raid, especially in combat.

Other choices

• Glyph of Shadow Word: DeathLevel 62A bit more damage once the target drops below 35% health.
• Glyph of Shadow ProtectionLevel 30Needs recasting less often on the whole raid, when this protection is useful.