Hmm.. looks like Jewelcrafting isn't either of the two best options for a tank in WotLK. I pulled this from a wowhead comment and checked some of the stats.. they appear to be correct:

[B1] Tanking:

*
Herbalism = 2000healing/3mins (11 heal per second), not on GCD can be tied to other skills to always be used.
*
Mining = 50 stamina
*
Alchemy = 320 HP (Flask of Stoneblood)
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Enchanting = 48 stamina
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Jewelcrafting = 33 stamina
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Blacksmithing = 60 stamina or 40 Def or 40 Dodge
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Leatherworking = 50 stamina
*
Inscription = 32 Dodge Rating
*
Tailoring = 300ap/15second proc from Swordguard Embroidery (highly not worth taking tailoring for this)
*
Engineering = variable based on value of crafted helm and hand enchants, gadgets are priceless (like a mother's love, not the good kind)

My personal suggestion:
Plate tank: Mining & Blacksmithing
Druids: Mining & Leatherworking
These combinations provide a large amount of stamina boost as well as access to relevant gear for your class to help out.

[B2] Physical DPS:

*
Herbalism = 66.7AP (average, requires consumables)
*
Skinning = 32 Crit rating
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Alchemy = 64 AP (Flask of Endless Rage)
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Enchanting = 64 AP
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Jewelcrafting = 42 AP or 21 AGI or 21 STR or 21 Crit Rating or 21 Haste Rating or 21 Hit Rating or 177 ArPen
*
Blacksmithing = 80 AP or 40 AGI or 40 STR or 40 Crit Rating or 40 Haste Rating or 40 Hit Rating or 280 ArPen
*
Leatherworking = 64 AP
*
Inscription = 64 AP
*
Tailoring = 300ap/15second proc from Swordguard Embroidery (highly not worth taking tailoring for this)
*
Engineering = variable based on value of crafted helm and hand enchants, gadgets are priceless (like a mother's love, not the good kind)

My personal suggestion:
Rogues, druids, (Shaman/hunter): Skinning & Leatherworking
Warriors, paladins, death knights, (shaman/hunter): Blacksmithing & Skinning

These provide the most benefit for your class, (with craftable gear that you can wear).

[B3] Caster DPS / Healing:

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Herbalism = 33.3SP (average, requires consumables)
*
Skinning = 32 Crit rating
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Alchemy = 37 SP (Flask of the Frost Wyrm) OR 13 MP5 (Flask of Pure Mojo)
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Enchanting = 38 SP
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Jewelcrafting = 27 SP or 21 Crit Rating or 21 Haste Rating or 21 Hit Rating or 9 MP5
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Blacksmithing = 46 SP or 20 Crit Rating or 20 Haste Rating or 20 Hit Rating or 16 MP5
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Leatherworking = 37 SP
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Inscription = 36 SP
*
Tailoring = ~24dps from Lightweave Embroidery, ~16mp5 from Darkglow Embroidery
*
Engineering = variable based on value of crafted helm and hand enchants, gadgets are priceless (like a mother's love, not the good kind)

So, it looks like Mining and Blacksmithing are back to being the best choices for a tank.. or Blacksmithing and Inscription for +32 dodge instead of +50 stamina. Jewelcrafting is worse than quite a few of the professions for tanks. The couple extra JC-BoP gems aren't that much better from the top BoE gems - not enough to make up the difference that +50 stamina from mining or +48 stamina from enchanting.