Number of the Beast - Iron Maiden
Quick listen, just 8 songs and 40 minutes. Has probably my favorite closing song of any album. It's the album I used to convince my bluegrass and folk-loving dad that metal had more artistry than he was giving it credit for. Bruce Dickinson's voice is unreal.
Definitely has the best scream I've ever heard on an album, and a song about the fibonacci sequence. What more can you want