Even though it doesn't make me feel very happy, for those of you out there who never see a drop, the PvP helmets make a very good substitution.
The new ilevel 371 Vicious Gladiators Scaled Helm is better than anything you'll se before the Cataclysm tier 1 raids. You could get ilevel 359 tanking raid drop -helmets that aren't as good as this one.
The ilevel 384 cousin doesn't fare as well when compared with its Firelands ilevel 378 tanking cousins, but it's obviously a step up from the 371. Observe that 'not faring as well' still means that the 384 PvP helmet qualifies as a perfectly valid 378 tanking helmet, albeit poorly itemized.
The Ruthless cloak, at ilevel 384, clocks in as the second best tanking cloak in the game, only beaten by an agility based dps cloak. You have to love Blizzard for itemizing gear properly.
So, what's so interesting about these metal hats? Well, you can buy Honor for Justice Points, and you can buy Conquest Points for Valor Points.