http://elitistjerks.com/f76/t35975-h...n_guide_wotlk/
WotLK added a lot of new options for meta gems to choose from. For all the comparisons I am using 1400 Int and 25114 mana as a base, approximately mostly epic gear that is favoring Int. I also assume a 6 min fight, 4 Divine Pleas, and 90% Replenishment uptime.
[Insightful Earthsiege Diamond] (5% chance to restore 600 mana with a 15 second ICD)
26.6 Intellect (After Kings/Divine Intellect)
399 mana at start.
399 mana from Divine Plea.
323 mana from Replenishment.
48 mana from Arcane Torrent, if you are a Blood Elf.
5.3 spell power.
0.156% crit.
4800 mana from proc. With ICD an average of 45 seconds per proc.
Total: 5921 mana (+48 if Blood Elf), 5.3 spell power, 0.156% crit.
[Ember Skyflare Diamond]
28 Intellect
420 mana at start.
420 mana from Divine Plea.
340 mana from Replenishment.
50 mana from Arcane Torrent, if you are a Blood Elf.
30.6 spell power.
0.168% crit.
Total: 1180 mana (+50 if Blood Elf), 30.6 spell power, 0.168% crit.