This is a thread to see what people's all time favorite albums are they can be from any genre even if they're not metal that's fine. Please only pick no more then 10 albums and explain why they are your favorite.
My 10 Favorite albums in no particular order are:
Dream Theater: Six Degrees of Inner Turbulence - When I heard this album I was in grade 7 and at the time my version of metal consisted of only bands like System of a Down, In Flames, and Shadows Fall. When I turned this album on my entire world changed it opened me up into the genre of Progressive Metal. This album contains 2 discs and both are amazing. My favorite songs on it are The Glass Prison, Dissapear, and Disc 2.

Ayreon: The Human Equation - This two disc album contains so many of my favorite singers such as Devin Townsend and Mikael Akerfeldt. It's a great progressive metal concept album. Lyrically this is probably my favorite album of all time because it tells such a great story.

The Mars Volta: De-Loused In the Comatorium - This Prog Rock album is off the wall and contains great jam and ambience sections. This album is also extremely sporadic and wierd and that's what I like about it.

Tool: Ænima - This is one of the best albums I have ever heard every song on the album is amazing and I can't think of anything on it I'd like to change it gives off such a cool vibe.

Blind Guardian: Imaginations From The Otherside - Most people say that Nightfall In Middle-Earth is the best Blind Guardian album but for me this album is my favorite Power Metal record ever. It has everything I want to hear in an album great leads and big chours. This album contains so many great songs like Bright Eyes, Script For My Requim, Mordred's Song, and Born In a Morning Hall.

In Flames: Colony - This album contains some great melodies and is the last great album from Melodeath band In Flames. The acoustic passages on this album are what make me like this album so much. They can take acoustic interludes and make them so good that they don't seem like filler.

Iron Maiden: Powerslave - This is my favorite classic metal album it contains nothing but memorable songs and riffs. This album also includes my favorite Iron Maiden epic The Rime of the Ancient Mariner.

Megadeth: Peace Sells... But Who's Buying? - This is my all time favorite thrash album and one of the most aggressive albums I have ever heard. On this album you can really feel how pissed off Dave Mustaine is and every song on the album is amazing.

Opeth: Damnation/Deliverance - This album contains one half of really great mellow songs that I can't get enough of and the second half of the album is heavy as fuck. This album contains both extremes of music which is why I like it so much.

Symphony X: The Divine Wings of Tragedy - Another great progressive album that contains some great keyboards and neoclassical shredding by Michael Romeo.