I don’t think “Greatest Hits” albums should be included. Just cheesy.
I've never liked Greatest Hits albums. Mostly because I enjoy the lesser played tracks on albums and often get tired of the hits. Led Zeppelin IV is a great example (though not a greatest hits album, itself). I'm tired of Stairway to Heaven, Black Dog and Rock and Roll. But still enjoy Four Sticks and Battle for Evermore.
But I guess the numbers don't lie. People buy them like crazy. Even the Eagles. I hate the Eagles.