I love Tool, they have the best sound and the deepest message. I like to listen to a tool album on headphones in the dark, it's like meditation, you can almost reach other states of conciousness just by concentrating on the music.
I can't wait for Tool's next album to come out, I heard it will be out in the spring of '06 but judging from how long Lateralus took to come out, it could take a bit longer.