I know the feeling!
I downloaded a couple of Opeth tracks off the net, purely by accident. I thought they were so good that I went out and bought ALL of their albums in one go.
I guess I haven't given them all the same amount of attention that others who bought the albums one at a time would have done, so in a way, my discovery of their sheer brilliance is still ongoing.
Still can't quite get my head around Orchid, tho'.