Probably something like this.
Pink Floyd - Wish You Were Here (1975)
My favorite album, by far. I think this is the Floyd album that got it all right. The composition and everything just comes together perfectly. All tracks are fantastic.
Much better than Dark Side of the Moon, and The Wall, with more personal and relatable themes, more even tops and lows, and overall, it's just more down to Earth, with a higher musical quality. (Doesn't mean those two are bad, but this is better.)
Honorable mention goes to Animals, that is almost as good.
Radiohead - Kid A (2000)
I can never decide if this or OK Computer is the best, I think it goes in periods. Right now I love Kid A over OK Computer, though.
This one is actually quite special, at first I hated it, and was greatly disappointed by it. Everything sounded like a complete hysterical mess, but something about it just struck me as being so interesting. So I continued listening, getting to like more tracks all the time, and now I can't understand how I could ever have disliked it.
The album just has so much character, it's very dark, twisted and mystical, which I just love.
David Bowie - Low (1977)
You know, David Bowie has made so many great and equal albums, that I already kind of regret putting this here, but on the other hand, this is probably the one I come back to, and declare my favorite, the most.
It's a very special album in that I can't really point out a single track that stands out as being particularly better than any other. It's just a case of everything coming together to form a whole. It's probably the best Bowie album, probably.
The Beatles - Sgt. Pepper's Lonely Hearts Club Band (1967)
This one is mandatory, I guess.
There's really not much to say, that hasn't already been said.