Earth

Earth is a band that has played many styles of music in their career. They are most famous for being pioneers of the drone doom genre. They have had massive influence on the bands that followed them is this genre, such as Sunn 0))) and Teeth of Lions Rule The Divine. Ex-members of Earth have gone on to participate in other metal bands in similar styles such as Thrones and Khanate.
However, Earth's musical style has evolved over their career. Their new music has turned away from the focus on drones, and incorporated eclectic influences and clean tone. By now, I might even go so far as to classify them as post-metal, or just general experimental. Throughout the changes in their style, they've maintained consistently high quality, and kept producing good music.

Recommended Albums:
That's difficult to say, because of their musical evolution. I guess I would suggest a couple releases to cover the different sounds.
Earth 2
Pentastar
Hex

Official Website
Official Myspace
Some mp3s are up on Southern Lord ( who rock, by the way)
Earth live