Jeff Loomis - Zero Order Phase. That album made him into my new favouritestestst instrumental guitar player. Far above Vai and Gilbert.
Others include:
The Formation of Damnation by Testament. Every single song is pure, compressed, fucking, win.
Slipknot's All Hope Is Gone qualifies, as the only songs I didn't like were the extra ones I had to find elsewhere.
Megadeth's Endgame was so awesome.
Meshuggah's Obzen for sure. Every song on that album basically puts me in a trance of awesome.
Now for some non-metal...
Pink Floyd's Dark Side Of The Moon and The Wall. Animals comes close.
I dug pretty much every track on Gary Moore's album whose title I forget. First song was called If The Devil Made Whiskey. Very likely that's the album title too. Great album that one.
Soundgarden - Superunkown is another classic that I never fail to enjoy all the way through. Lights out, headphones on, chilled out.
Oh an, um... um... the soundtrack to Repo! The Genetic Opera. >.>