Here are the gems and enchants that are relevant to tanking. This is from my limited prot pally point of view. I don’t know what gems or enchants the other tanks need but I’m sure that most are the same.
Enchants
Head

Arcanum of the Stalwart Protector revered with Argent Crusade

Shoulders

Greater Inscription of the Pinnacle exalted with Son’s [...]

This past weekend was a great weekend for my pally. I got a quite a few achievements, raided Naxxramas as ret (I actually left with four drops) and I bit the bullet and respecced prot and tanked my first WotLK instance, a heroic one at that!
Naxx
I raided Naxx with my guild on Friday and Saturday [...]

I put on my prot gear this morning, got a Frosthide Leg Armor kit filled in the empty gems slots green gem slots I had and logged out before work. When I left home, I was sitting at just under 20k health.
I want my health to be 24,000 unbuffed.  I’ve been looking over the spreadsheet [...]

Wrath of the Lich King leveling is insanely easy! I started out in  Howling Fjord. After I finished that zone, I went to the other starting zone, Borean Tundra, to do the quests there, since I figured they would be easy XP for me.
That was a great idea if I have to say so myself! [...]

On Sunday night, I tanked for the second time.  I tanked slave pens so that I could finish up a quest that netted me 22k experience and some rep.
I’d like to get to honored with Sporeggar so that I can buy the best AoE grinding shield for pallys, the Petrified Lichen Guard! I only [...]

I tanked The Underbog last night. It was my first attempt at tanking and it was a lot of fun! There were 3 wipes for reasons that I felt were my own. Two wipes on a pull between bosses 2 and 3, just before the hunter boss.
I had to respec to prot last night so [...]