This is "favorite album" in disguise, I think... but whatever. I'll always pick whichever category Still Life is in, but I think if you're really going to divide it up, it should be like this...
Orchid / Morningrise
MAYH / Still Life / Blackwater Park
Deliverance / Damnation
A bit more limited, and a bit more obvious as to who the winner will be, but I feel like Still Life reflected, more than any other album, great, great songwriting ingenuity. I feel like some of the other albums were a bit more bland (*cough* D1, D2 *cough*), but Still Life was alot different. BWP was a great example as well... also, probably their overall best album.