Mahavishnu Orchestra - The Inner Mounting Flame

I've owned a copy of this since I was 14 and it still gets played all the time. It's blend of high volume guitar wailing and intricate rhythms just fits the shape of my brain. Through in some spirituality and ambience and you've got a record that was an absolute game changer, all but inventing inventing jazz-rock all on its own. It peaked at #89 in USA and amazingly didn't chart in UK at all.