I saw an addon once that would let you choose to hide/show your helm/cloak and saved it to which spec you were in.
It was a lot like Mr.DressUp
http://www.wowinterface.com/download...MrDressup.html but saved it per spec...
So if you liked your Tanking Helm, but didn't like your DPS helm, you could show the tank helm, but when you switched to DPS it would auto hide it, and vice-versa. Can't find it though... anyone know which I'm talkin about?
EDIT:
I just found HelmNCloak
http://www.curse.com/addons/wow/helm-n-cloak on curse but I know I saw a different one here.