As a DK tank, I use the Monarch Crab and the Ruby Hare socketed with parry/stam gems. Considering the socket bonus of 9 stam, that's a good 95 stam and 16 parry rating, compared with the 111 stam and chance to proc of the Essence of the Gossamer.
My Gossamer, Valor Medal, and Repelling Charge are banked atm, but I'll probably start carrying them in my bags as a fight-to-fight thing.
Typically, I tank everything with the Crab and Hare though.
I *was* using Gossamer beforehand, but
Loot Rank for WotLK seemed to think Hare was a bit better, and since resocketing and giving it a shot, I'd have to agree.
When time/money allows, I plan to get the +str Greatness card to replace the Hare with. I doubt the crab will get replaced anytime soon.