Well, I couldn't live without a good 20-30 albums, but a few are just absolutely essential to me.
Smashing Pumpkins - Mellon Collie and the Infinite Sadness
Kyuss - Kyuss/Welcome to Sky Valley
Deadboy and the Elephantmen - Demo
Earth - 2

and just on the edge of favourite would be:

Black Sabbath - Master of Reality
( Ttssattsr perpetual backache of the damned, Mon 11 Aug 2008, 19:22, archived)

Nah, I'll let you keep three of them...
but I'm having Mellon Collie

*steals*

*runs away*
( SubCulture Hero ... ... He... .... Comes ... ...., Mon 11 Aug 2008, 19:30, archived)

Oh hell no. I have the triple LP of it too. :)

( Ttssattsr perpetual backache of the damned, Mon 11 Aug 2008, 19:30, archived)

Am I right in thinking that it has a different tracklising and a couple of extra songs?
I can't get my head around it with a different tracklisting.
( The Hedgehog From Hell 's days are numbered, Mon 11 Aug 2008, 19:32, archived)

Yep. And it also is fucking expensive. :(
The alternate tracklisting is actually pretty great, although I do end up humming the intro to the next track from the CD version.
( Ttssattsr perpetual backache of the damned, Mon 11 Aug 2008, 19:39, archived)