I recently picked up 4 albums and have been listening to them nonstop, so i can't choose just 3. Forgive me if they look "expected" for DTF:
Pink Floyd -"Wish You Were Here"
Emerson, Lake & Palmer -"Brain Salad Surgery" (not the version that breaks up Karn Evil 9 into 4 tracks, it is 29 minutes of glorious prog)
Rush -"Moving Pictures"
Opeth -"My Arms, Your Hearse"