Strength and Anger and it's not close. It's an absolutely engrossing experience, a hall of mirrors displaying numerous faces of hate. ultimately culminating in the pure, hateful, stillness of the ambient meditations. A true masterpiece.
I haven't listened to Forest Poetry in a few years, but I remember it being solid but it lacking the vision of Strength and Anger. I really don't like the drum tone on s/t and find it to feel more like a grab-bag than a true album. The Ildjarn/Nidhogg EP is killer.