Probably one of my single-most favorite albums of all time...
Tool - 10,000 Days
My opinion, one of the best "hard progressive rock" albums of all time. The musicianship is top notch (listen to track 4 ~5:45 in to hear some of the funkiest bass lines), music is dark but compelling, recording is excellent. It grabs me every time I hear it.
The first time you hear it, if you aren't into this kind of music, it helps to have a little buzz, be totally relaxed and just chill.
