All worthwhile music in any period is an experiment - if the composer/performer is not pushing the boundaries somewhere then the result will ultimately be bland and uninteresting.
i'd mostly agree with this (although i do own a few awesome albums, from various genres, where there's nothing new being done per se, the band/artist is just taking something that's been done, but doing it REALLY well), but a band who intend to push boundaries aren't necessarily viewing their album as an experiment. there's nothing wrong with experimenting, but not at the expense of having any emotional impact.
sure, experimental music can make you think. but all i think when i listen to, for example John Cage's
Music of Changes, is "he's experimented with a new method of composition, using chance. it's obviously not a great method, as the end result is horrible." maybe it's just that i look for different things to get out the listening experience, because to me, it's those hair-on-the-back-of-your-neck-standing-on-end, shiver-down-your-spine awesome moments, combined with the emotional impact of the music that keeps me coming back, and i can't get that out of most experimental music.
i do Music Tech, btw. our lecturer is a fan of experimental music, and so he tends to slant the few composition modules we do towards experimental areas.
oh, and on-topic (sorry!) - "Bad Devil" by Devin Townsend.