tool (official, wikipedia) is one of my favorite bands and has been for years. i started listening to them through a friend i made in high school, whom i've by now grown apart from and lost contact with, and who was equally into nine inch nails, pearl jam and alice in chains around that time.
we're talking around 96-97, their album aenima was recently released and i heard it at my friends place and liked it well enough to borrow it and tape it. it wasn't until a couple of years later that i grew to love it like a part of my own body. once that happened i remember listening to it again and again, loud!, and actually feeling the changes in mood and rhythm in my heart. and i still do. it's a very emotional album and, while not as focused perhaps as their two later albums but, artistic.
i'm not a great authority on technicalities in music (read: like my dear friend dave) which makes it hard for me to explain its effect on me, but tool has, unlike any band in the genre, an artistic element to their music, and with that i don't mean lyrics and artsy stuff that other bands indeed have, but the music itself. their albums sounds like a beautiful painting, or even a perfect brush stroke of thick paint. it's as if the intensity of the music follows an emotional pattern, something that i can really relate to.
the singer, maynard keenan, makes it perfect. he has a range of voice from soft whispers to full screaming that sounds good! he both sings and screams with emotion and his voice can make me both cry and scream. they way he sings them, he can pull of songs like hooker with a penis, dealing with a poser that's made him angry for criticizing them for selling out - that would make any other singer sound obnoxious and even embarrassing, sounding genuine, at the same time make songs like pushit, dealing with the emotional backlash of loving a dependent (i think, could be both related to depression and drugs too), sound so emotional it gives me real angst listening to it.
everything just comes together great; the music, the lyrics and maynard's voice. this goes for their live performances as well. i've seen them twice (at roskilde festival '01 and '06) and the first show was as close to having a religious experience as i've ever came, in the sense that i experienced something that i can't explain, something that made me - for lack of a better word - high. next to the above mentioned elements of their music, the visual impression took it a step further and it was truly an extraordinary experience.
the two later albums; lateralus and 10,000 days, is even more conceptual. the lyrics seems to go together in obvious as well as non-obvious ways. the music moves in cycles almost, where you recognizes things here and there and it takes quite a few times listening to the albums to make out the pattern. also, listening to tool is listening to albums, not songs, because if you split the albums and listen only to the songs randomly you'll be missing so much. listening to one song by tool is like watching only 15 minutes in the middle of a film.
generally i think you can say that tool demands a bit more from their audience than your average band and i know i'm not the only one with this opinion. i know i've read before that, like reading literature or watching movies with lots of references makes you feel smart and involved when you get the references - especially the obscure ones; tool makes its audience feel smart and involved, and i agree. because the effort pays off! there are hidden aspects to their music that you can't find the first or second time you listen to their albums. but once you do, it stays with you.