Your Favorite Concept Album

Symphony X - The Odyssey.
Blind Guardian - Nightfall in Middle Earth (Love the book too).
Gamma Ray - Somewhere Out in Space.
Dream Theater - Scenes from a Memory.
Ayreon - Into the Electric Castle.
Grave Digger - The Grave Digger.
Kamelot - The Black Halo.
Rhapsody - Symphony of Enchanted Lands (Part 2).
Avantasia - The Metal Opera Pt. 1.
Angra - Temple of Shadows.

I have more, but this is my top 10.
 
Still Life by Opeth - the clear winner in terms of listening time
Blood on Ice by Bathory - I find this much more effective in terms of drawing me into the story; incredible atmosphere and melodies, lots of emotion
Scenes From a Memory by Dream Theater - haven't listened to this in a long time since it's not my preferred musical style, but still damn incredible
 
Edge of Sanity - Crimson (even though the story is pretty lame, musically it flows beautifully)

Opeth- Still Life

Ephel Duath - The Painter's Palette

Orphaned Land - Mabool - Great concept of the Ark and the Great Flood, even if a bit too religious for my liking. The construction of this album is second to none. Starts with an explosion of melodic death riffage, then goes more prog, then folk, then comes 'The Calm before the Storm', and finally climaxes with two epic pieces symbolising the flood itself.
 
Edge of Sanity - Crimson (even though the story is pretty lame, musically it flows beautifully)

Opeth- Still Life

Ephel Duath - The Painter's Palette

Orphaned Land - Mabool - Great concept of the Ark and the Great Flood, even if a bit too religious for my liking. The construction of this album is second to none. Starts with an explosion of melodic death riffage, then goes more prog, then folk, then comes 'The Calm before the Storm', and finally climaxes with two epic pieces symbolising the flood itself.
I agree with all those, and in addition:

Ahab - The Call of the Wretched Sea
 
I still like the Original Mindcrime and anything by Kamelot.

Savatage: Streets,Dead Winter Dead,Wake Of Megellan,Poets & Madmen!!:kickass:
 
I forgot to include these two in my previous list:

1) Nevermore - Dreaming Neon Black (Amazing stuff).

2) Evergrey - In Search of Truth.