Here's what I've got so far.
Obscura- Gorguts
No matter how many times I've listened to this, it feels like I discover something new each time, should help keep me sane.
Olm- Hadal Maw
Only found this a few months ago, but it has rocketed its way up my favourites list. Has similar benefits to Obscura.
A Real Live Dead One- Iron Maiden
The first real metal album I ever heard (I had previously only really listened to KISS and Guns N' Roses as far as anything really close) plenty of classic tracks, great performances and the crowd chanting is awesome.
Deicide (s/t)
I don't fancy the idea of dying on a desert island without Dead By Dawn or Lunatic Of God's Creation.
Peactice What You Preach- Testament.
Good blend of catchiness and menorability with heaviness and interesting writing, interchangeable with a fair few thrash albums.
Rust in Peace gets an honerable mention as it might make it to my favourites list, but I think I've well and truely listened to it for enough times that it would bore me, possibly to insanity. I'm not sure if Deicide is the Deicide album I want to take, also I might want to make room for something long and progressive, but couldn't seem to fit it in. Dunno.
Just remembered I'm wearing an Iron Maiden jacket over a Hadal Maw shirt, I wonder if these decisions were influenced.