Ta da! Here I am. So educate me.
As an absolute newbie, what must I absolutely listen to first?
What do I need to know about?
TIA 
(ETA The back catalogue is overwhelming; so I've started at opposite ends: oldest and newest...)
Sheena, welcome on the Board.
I'd recommend you to check "All of This The live Rarities" CD and old Marquee gigs from the 30th Anniversary CD/DVD's in a case of older 80's live sets, then dive in to the albums like Thunder & Consolation, Impurity, Eight, High and then Between Dog & Wolf. All of that in one day as a hardcore set! And after taking some breath, listen to Between Wine & Blood which is only few songs.
