I'm gonna write a list of some of my favourite albums from each year, starting from 1967 (mainly because any further back is just pointless -- I've heard only 4 non-Beatles albums from before 1966) with a little explanation or something. So let's get started without further adue:
The Moody Blues: Days of Future Passed
A symphonic rock album with a few hints of early prog in it. A pretty nice album to sit down and relax to every now and then.
The Jimi Hendrix experience: Are You Experienced
The debut album by the Jimi Hendrix Experience is a brilliant debut album. There's so much guitar wankery in here that it's ridiculous, but when you're this good with a guitar it's not like anybody can say anything to you. This album rocks hard, jams hard and is funk-filled throughout.