I'm not a huge fan, but In the Sign... is the only 80s BM album that I actually like and some of the viking-themed tracks are also brilliant.
One of my favorite interviews with him: Quorthon (Bathory) interview A highly intelligent, perceptive human being. We need more like that. His loss is keenly felt.
Bathory was one of the first black metal bands I could tolerate back in high school. Loved all the albums, except the shitty thrash ones he tried to pull out his ass. The rest is great.
This man was far more intelligent than most metal musicians, and when he was on, he made GREAT music. The second album and "Hammerheart" will always rule my ears.