There are sub genres within Prog Rock (not Progged Rock, Joel ). There's Art Rock, defined by bands like Rush and The Moody Blues. Canterbury Rock probably solely defined by Caravan. There's Prog Folk, Jethro Tull being the most notable within the genre. Progressive Metal: Dream Theater, Symphony X, etc.. This type of prog didn't become popular until the early nineties and is known as Neo Progressive Rock (go figure). Symphonic Prog is the largest sub genre of prog rock, which includes bands like Genesis, Yes, early King Crimson, ELP, Camel and Gentle Giant. Then you have your prog rock from specific parts of the world, notably Kraut Rock and Italian Prog. There are other less important sub genres as well.

Early Pink Floyd is Psychedelic Rock, or Acid Rock, which is not considered a part of Progressive Rock. With the eventual release of DSotM, Pink Floyd could then be considered part of Space Rock, a sub genre of Prog Rock, along with Hawkwind, the other great band of that genre.

There's debate over whether or not Radiohead is Prog music. I say no, but it's up in the air for now.

Yes, I'm a fan of the early stuff.