The consecrate libram is great for one thing, getting the Epic achievement. Consecrate scales so poorly with spell power that the libram is a complete waste. Test it yourself, take off the libram, consecrate on a mob, watch the ticks, and then try it again with the libram equipped.
I have it, but the only time I equip it is to log out in a high iLVL set so I look good on Warcrafter (blame my GM).
The libram of obstruction is the only tanking libram at the moment, use that and only that.
Never gem for parry. Yellow sockets should get +def+stam gems if you're looking to match the bonus.
With the glyph of Seal of Vengeance/Curruption you're well over the expertice soft cap. At the moment, there aren't any better tanking glyphs to swap in, so I'd change your Sabatons of Endurance for the emblems of valor boots to shed some expertice and gain some avoidance.
On your spec:
Benediction is a waste of talent points. If you have mana issues, pull more trash. I know you need points to get into Pursuit of Justice, but I'd rather put Tuskarr's Vitality on my boots for an increase in speed, and spend the talent points elsewhere.
I use this spec:
Talent Calculator - World of Warcraft
It leaves two points to put where you like, I usually throw them in improved hammer of justice.