Well, i guess its my turn to post. First of all, id highly recommend the 70s prog thread still on this forum started long ago, which has tons of information from myself, abhorsen, some retired members and even mikael. But if youd rather not browse through it (its hundreds of pages i beleive now), then i dont blame you, and ill do the best i can to summarize a lot of this fantastic and often dismissed or overlooked genre right now. If "prog metal" is what youre after, then id suggest looking elsewhere for i care not for that naive genre and feel theres only a few bands which actually fit that tag (opeth, enslaved, arcturus, and a few others). If you want the real deal, then please continue.
Pysch: The sound which would later become the progressive sound, started in drug induced, adventerous use of sound, effects and a cerebral sophistication developing a whole new era in rock music. Oganic AND electric, it spawned a whole new way of thinking and expression. EXAMPLES: Pink Floyd, Aerevons, Gandalf, Soft Machine, etc.
Proto Prog: The starting bands who helped create and develop this genre. Not full blown progressive rock in the stereotypical sense, but all contributed to the sound which would take shape later on. EXAMPLES: The beatles, the moody blues, procol harum, the nice, etc.
Symphonic Prog: This is the sound most people equate to the term "prog". Yes, Genesis, King Crimson, ELP, etc. Coming from britain, these were the most influential and respectively most talented acts (usually pretentious and stubborn too). Displaying long, complex song structures in most cases, and no boundaries for experimentation and storytelling. MORE EXAMPLES: Jethro Tull, Gracious, Camel, etc.
Italian Symphonic: Following soon after the british burst of talent, was the italians. Inspired a lot by Genesis, King Crimson and the like, they brought a different cultures take on that sound, incorporating classical elements, a more wide variety of instrumentation, and in many cases...vocals in their native tongue. Some would dispute these bands are better than the british counterparts. EXAMPLES: PFM, Celeste, Banco, Le Orme, Goblin, etc.
Canterbury Sound: Although a small grouping, this genre is essential to me, for its maybe my personal favorite of all the subgenres. Located in the small portion of england, it was an offshoot of proto and psych, which turned into a very jazz influenced form of non grandiose and commercial prog like Yes or Genesis. EXAMPLES: Caravan, Hatfield And the North, National Health, Gilgamesh, etc.
Folk Progressive: A genre which was half folk inspired, using many acoustic instruments and patterns, while maintaining the progressive forward thinking advantages of the other genre...creating a very organic and interesting alternative to the bombastic symphonic alternatives. EXAMPLES: Mellow Candle, Tudor Lodge, Trees, Extradition, etc.
Kraut Rock: German scene, consisting of a lot of experimentation, and often un-uniform song structures and aproach to achieve as weird and interesting songs and expression as possible. Some bands would stay more stream line and infuse the symphonic genre with this as well, to keep a more song oriented and commercial sound. EXAMPLES: Grobschnitt, NEU, Agitation Free, Birth Control, etc.
Modern Vintage Progressive: Bands which are modern and current, but are set out to make similar music to the classic bands. Not as "progressive" as maybe they should be to achieve the title, but many do that sound VERY well and are still fantastic listens. EXAMPLES: Anglagard, Anekdoten, Porcupine Tree (early), Areknames, Liquid Scarlet, Circulus.
Neo Prog: Innovative, creative and talented bands staying quite true to the term "progressive" in that theyre making new music using familiar elements, but in a way not done before. EXAMPLES: Radiohead, Opeth, Paatos, The Mars Volta, Porcupine Tree (again).
alright folks, there is a brief rundown so you know what to explore. ill continue to post more recommendations here if this thread stays alive, or in the already existing prog thread if people frequent that one more now. happy hunting, hope this helped.