Vanilla - MC, BWL, Skeram in AQ40 (First boss)
TBC - Kara, SSC, TK, Gruuls, Mag, Hyjal, BT, Kalecgos in Sunwell
Wotlk - Naxx (Server first), Sarth, Malygos (Server first), Ulduar, ToC (all heroic except last boss, never killed it due to trying for Insanity every time), ICC (11/12 H25)
Cata - All Reg - BoT, BWD, DS (Pre nerf)
I have a Warlock and a Paladin to play on and I have most of my experience healing on my Paladin. If you are interested, please leave a reply.