I disagree with swizzle's fire bis list.
Mine comes out at: 19167.27 (including 30% buff)
Swizzle's: 19021.22 (including 30% buff)
Listing:
Santified Bloodmage Hood (chaotic skyflare + sp-spirit)
Amulet of Silent Eulogy (SP+Crit)
Sanctified Bloodmage Shoulderpads (SP+Hit)
Frostbinder's Shredded Cape (SP+Hit)
Sanctified Bloodmage Robe (Runed Card + SP-Spirit)
The Lady's Brittle Bracers (SP + Crit)
Gunship Captain's Mittens (SP-Spirit, Runed Card)
Crushing Coldwraith Belt (SP-Spirit, 2x runed card)
Sanctified Bloodmage Leggings (SP-spirit + sp-crit)
Plague Scientist's Boots (SP-Spirit + Runed Cardinal)
Ring of Rapid Ascent (SP-Spirit)
Ashen Band of Endless Destruction (SP-Crit)
Phlactory of the nameless lich
Dislodged Foreign Object
Bloodsurge(284) - Runed Card
Shadow Silk Spindle
Corpse Impaling Spike (SP-Crit)
Baring in mind this is for the Horde (no heroic presence, in which case dump the hit gems) and taking Misery/Imp Fairie Fire into account. Now this list does leave you short of 5 hit rating, either gem it or expect to miss every once in a blue moon.
Using t10 hc sanc hands results in a dps loss according to rawr. As does using plaguebringer's stained pants over t10 hc leg's.
I agree with gemming hit, but if for example i'm losing 60-70 haste/crit for 30 hit rating off a particular piece, i'd rather gem for hit as the haste/crit rating will vastly outweigh the additional unneeded hit.
60 or 70 haste/crit or a piece which totally negates the haste or crit and gives you 30 hit more than you need. At the end of the day, to get the absolute max from your gear in icc25hc, you need to gem for hit (2x 12SP + 10 hit with my bis list). No matter how i do it, it's a considerable dps loss using for example Valanar's other signet ring/Loop of the endless labyrinth (to get the additional hit needed) instead of using ring of rapid ascent. Lose 60 crit/haste or gem a couple of veiled ametrines and not lose any spellpower in the process (and gain 60 crit!). It's a no brainer!
It seems that at the highest points of gearing (full 277) for fire, haste starts overtaking crit again.
In conclusion, Gunship Captains Mittens! :P