The only reason I didn't vote for TOOL is because I figured that everyone else would and that BTE would end up needing more support. Stupid me.
There aren't many bands like TOOL. They make no attempt at being radio friendly. I think that's why some people haven't heard a lot of them, but they have a lot of good stuff. Sober is good and it's probably what their most known for, but on that album (undertow) my favorite songs are prison sex, swamp song, and intolerance. Everything on Aenema (3rd album) is excellent. Lateralus (4th album) is really good too, but a little subdued comparatively, which isn't a bad thing, but if that's not your style.... The title track stands out in my mind off that one. Opiate (1st album) I haven't gotten, but I intend to. I've heard the song Part of Me off that one and it's pretty good, but I get the impression it's fairly obvious how old the album is.
Anyway they're a bit of a harder rock band, but don't fall into any of those cliches. I wouldn't call them metal like the media does, but really I can't classify them at all. Post modern rock maybe. If you don't like hard rock though, you might not like them, but like I say, you can't really classify them. Definitely give them a try though.