I don't know a thing about your tastes, but to break it down for you:
Burzum (s/t): A bit raw, flying in the face of the death metal standards of the time.
Det Som Engang Var: Not quite as raw, more "experimental".
Hvis Lyset Tar Oss: Bleak in its beauty, ritualistic. My favorite.
Filosofem: Has a more decrepit, vaguely "industrialized" atmosphere.
Dauði Baldrs: No more black metal, simple keyboard-based neoclassical.
Hliðskjálf: Similar to Dauði Baldrs, but sounds better.
The debut is probably the most accessible of them, if that helps.