I'd say Alternative4 even though it is underated by many.........
I don't want to comfuse you but none of Anathema's albums has ever dissapointed me......
Silent Enigma started me on Anathema, its an unique album... since most doom bands start wih a Serenades style and from Eternity on Pink Floyd had already done that.
The Silent Enigma is great because its right in the middle of their desenvolvement.