Tool are one of my favourite bands. Their Undertow, Aenima and Lateralus albums are three of the few albums in my collection I can listen to all the way through without feeling compelled to skip tracks or fast-forward parts (something they have in common with Opeth). The music they make is original, intelligently structured, and quite unique. As for wanting to be a progressive band - well, if they can pull off the intricate song structures without resorting to the self-indulgent fret-wanking that most prog bands feel compelled to inflict on their listeners, that's fine by me!