Like most people, I like things. What things do I like? Lots. Here is a list of the things I like most, in at least a vague semblance of order. Maybe you like them too; maybe you don't. If you've never heard of them, give them a try; you might like them, or you might hate them, and then at least you'll have me to blame for it.
(For the purposes of this discussion, I'm talking about classic Yes, i.e. the period from The Yes Album to Relayer, and the later stuff in that style. The other incarnations are good too - don't let the diehards tell you that 90125 isn't a damn fine album. It totally is.)
Yes is kind of like the 1967 Beatles, if you stripped out the LSD and Dada and replaced it with baffling '70s pseudo-spirituality and made the songs four times as long and/or chained together. Kind of. Whatever it is, it's very, very good. Not everything of theirs holds together perfectly - Relayer builds up some ferocious energy only to mellow it out somewhat unsatisfyingly in the last ten minutes, and Tales from Topographic Oceans would be killer if it were only half as long - but every album in this period contains a surfeit of must-hear classic progressive rock.
Must-hear album: Close to the Edge
(Again, I refer to classic Genesis - Trespass to The Lamb Lies Down on Broadway, with honorable mention to the first two post-Gabriel albums. If you prefer the unrelated '80s synthpop band that coincidentally included most of the lineup, you and I have nothing to say to each other.)
If you replaced Yes's jazz roots with music-school classical obsession and upper-class British fastidy, you'd have Yes keyboardist Rick Wakeman. But if you threw in a penchant for clever wordplay and the same sort of English mysticism that C.S. Lewis displayed, you'd have Genesis. Lots of weirdness, lots of lush Mellotron-backed arrangements, and a lot of solid songwriting ability backing up all the esoteric stuff and making it thoroughly catchy. Genesis does have a problem with extended filler sections that go on significantly longer than they should, but there's so much else to love about it that it doesn't matter.
Must-hear album: Foxtrot
(Lineup? There's so many different lineups in King Crimson that even they admit that they've lost track. We'll just say In the Court of the Crimson King to Red - there's probably some fine material afterwards, but it's not for me.)
If you took Yes's jazz roots and moved them to the forefront instead, and you stripped out all the new-agey spiritualism and replaced it with dense, brooding lyrics and music and sudden left turns into manic rocking, it would be nothing at all like Yes. It would be King Crimson. These albums are absolutely fascinating, both as obvious influences in the development of every other progressive rock band, and in their own right. The only real criticism I can make is that they put long-form improvisations (a staple of their live shows) onto most of their albums - but they never seem to pick the good ones.
Must-hear album: Larks' Tongues in Aspic
If you took Yes and made it exactly like Yes, except from Illinois, you'd have Starcastle. Despite the obvious influence, they actually do take things in their own direction - a little less jazz/classical, a little more extended '60s pop. It's good, even if it's not as good as its inspiration.
Must-hear album: Starcastle
If you took the "if you took" running gag out back and shot it, grabbed Greg Lake of the early King Crimson lineups and paired him with a master drummer and a keyboard wizard obsessed with early-20th century classical music, you'd have ELP. Somehow or other they became the scapegoats when progressive rock fell out of fashion, and the only song most people have ever heard is a bit of (admittedly catchy) fluff they didn't even want to release, but don't listen to the hate: ELP is a fantastic band. Keith Emerson is a master keyboardist and a solid songwriter who works in his esoteric obsessions without diluting the rocking, Lake can sing like anything and contributes some fine softer numbers, and Carl Palmer keeps things moving with aplomb. Just don't bother with Love Beach.
Must-hear album: Tarkus
What's this? A progressive-rock band where the singer is a woman? Yes, it's Renaissance, and in addition to that novelty, they're one of the few groups that both include an orchestra as a main part of their sound, and do it well. They're not quite as engaging as some of the bigger-name progressive rock bands, but still quite good. Definitely worth a listen.
Must-hear album: Novella
On the subject of progressive rock bands with lady singers, Curved Air. They're...well, they're only kind of rock, far more drifty and ethereal than wild and exciting, but they're very engaging nonetheless. The thing I find most interesting about them is the Victorian Gothic feel to a lot of their lyrics - if Evanescence had been formed in the '70s, I think this is what it might have sounded like.
Must-hear album: Phantasmagoria
Okay, everyone has heard of Pink Floyd. But how many of you have heard anything that isn't The Dark Side of the Moon or The Wall? Not that they aren't fine albums, but there's a whole lot more in their discography worth listening to. The whole period between The Piper at the Gates of Dawn and The Dark Side of the Moon is criminally under-rated. Not all of the songs on all of these albums are great, but the stuff that is good is very, very good. Check it out - you won't regret it.
Must-hear album: Meddle
Generally classified as progressive rock, but what Focus reminds me most of is "elevator music"-type light rock, if that abortion of a genre were suddenly and mysteriously infused with energy and talent. Focus is probably best known for the 1971 hit "Hocus Pocus" (the rock-yodeling song,) but there's plenty more worth listening to.
Must-hear album: Focus III
The first of the last of the true Christian intellectuals, and almost certainly the greatest Christian writer of the 20th century. Lewis was a hard-line rationalist as a young man, but although he returned to Christianity, he kept a firm hold on the critical-thinking and analytical skills he'd developed. It's this that makes him both one of the most eloquent theologians out there, and a fascinating and far different character than many of the people who profess devotion to his works seem to think.
Must-read book: That Hideous Strength
Stephenson writes thoroughly engaging science fiction (and is one of the few who actually manage to come up with neologisms that sound like things anyone, anywhere, ever might actually use,) and while he has a tendency to sidetrack the story every ten minutes to deliver a massive infodump on whatever subject is tickling his fancy, he manages to make it stay readable. It's like someone stripped the pretentious punk-ness out of cyberpunk and filled the hole by mainlining fun directly into the text.
Must-read book: In the Beginning Was the Command Line (thought I was going to say Snow Crash, didn't you?)