I'm mostly into blues or country; singer/songwriters.. perhaps it's easier for me to comprehend what they are doing.. regardless, to stir things up:

Here's King Crimson. A very unique band with a long history. Look at the stage presence here, this is 70s most out-there and heavy band, and they all are suited up! The founding member, and all the guitars, are hidden in the back, behind three (sic!) drum sets. If you haven't herd of them, they are led by Robert Fripp, an eccentric savant. I think his attitude best describes one of his quotes, with which i totally agree: "Unless you have seen a band live, you don't quite have a right to hold an opinion about it; secondly, unless you've seen a band live three times, your opinion is not likely to be substantial."

As a starter, something not so progressive --- Starless.