For me the perfect albums are the ones in which all of the songs come together to tell a story. While there may be one or two hits that get a lot of airplay from them, they are part of something more cohesive. They aren't a bunch of great songs on one album (I mean, those do make a great album, but could be put on a greatest hits and still be good), it is one album you play from start to finish that tells a story or a series of stories.

The two albums that come to mind that are little bit more modern-
Ben Folds Five- Reinhold Messner
The Mars Volta- Frances The Mute

There are a lot of albums like this, and they are typically not the artists most popular album, and usually take awhile to appreciate what they are. We are so used to listening to a bunch of great individual songs, it is tough to listen to these albums that are more or less "stories".

Damn, I knew I've heard that dude before..... I have listened to his Dangermouse collaboration "the Mouse and the Mask" about 1 billion times. He has a great voice.