This Was (1968)

Stand Up (1969)

Benefit (1970)

Aqualung (1971)

Thick as a Brick (1972)

Living in the Past (1972)

A Passion Play (1973)

War Child (1974)

Minstrel in the Gallery (1975)

Too Old to Rock and Roll (1976)

Songs from the Wood (1977)

Heavy Horses (1978)

Storm Watch (1979)

A (1980)

I must agree for TFK !!!

Univers Zero

XTC

Anekdoten

Bark psychosis

Threshold

Marillion

IQ

Rush

Spock's Beard

Riverside

Thinking Plague

John Zorn's Simulacrum

Univers Zero and Cardiacs already mentioned, but good picks.

I discount bands that make the same album over and over again (even if it is a good one) and also those with a small discography (fewer than seven studio albums; arbitrary I know).

I was tempted to add Magma, but although I don't dislike Merci the way many do, it's still not on a par with their other work.

Univrs Zero 

Magma and VDGG come close. Agalloch is also stellar across the board but only have 5 albums. 

Cardiacs & XTC are a good shout.

Nemo/JPL

Deerhoof

 

Porcupine Tree

JTull

The Flower Kings

The Pineapple Thief

Riverside

Marillion

CAN

I suppose not all that many will agree with me, but these are the ones I can think of that made almost nothing but great music for more than ten years:

The Residents 1972-1984

Art Zoyd 1976-1987

Magma 1970-1981

Other than that: The Necks, Embryo, Peter Hammill/VdGG, Univers Zero, Egisto Macchi, Bolt Thrower, Can, Radiohead, Mal Waldron, Popol Vuh, McCoy Tyner, Robbie Basho...

The correct answer.

DJAM KARET — they do heavy prog, they do ambient, they do pastoral, they do symph — no one style can box these guys in.

GOBLIN — apart from the bizarre, if fleeting, detour that is the album Volo, every soundtrack and original record has something to offer, and some of them — like Dawn of the Dead, Roller and Suspiria — are undisputed classics.

KENSO — one of the best bands of the last forty years, period.

KING CRIMSON — self-explanatory.

I surely wouldn't stop in 1987; these days I'd even rate Häxan, Metropolis, and Phase V over anything they did before (that may be just my weird taste though). I really take all they did from beginning to end (OK I don't know whether I'll spin Pure Noise again but otherwise...)

Dellinger wrote: For me it's got to be Pink Floyd. I really like just about all their albums, and there are very few songs I actually dislike (though, of course not all songs and albums are as brilliant as the best ones). Actually, even their "bad" albums end up being enjoyable for me.

To me Pink Floyd were consistently different too as no two albums sound especially similar, with the exception of the post-Waters era stuff. They did have their low points (More, MLR) but they are still better albums than what most other bands could manage in my opinion.

Mad bonus points to you for Death, Atheist, Hramonium, and GG!

I'll add:

From the old days - King Crimson

Nowadays - Mastodon

(This is my superficial, 1-minute answer; Obviously, I adore both bands and I honestly believe they are shockingly consistent)

Breathtaking, incredible run. 

And that makes it a very difficult question indeed. As a Queen superfan, I can say I don't think they have any bad records, but none that are sub par? That's a different story. 

The question also implies that a band has a decently long recording career, effectively ruling out those one-and-done RPI greats. I wonder... this is probably controversial and tbf I haven't listened to every album, but perhaps Dream Theater qualifies? I realize The Astonishing is a big sticking point with a lot of fans, but that is one I have listened to, and I think it's great! Not quite at the level of their best albums, but I don't find it anywhere near reprehensible like many seem to. I guess that's the answer I'm going with. Until I hear a sub-par Dream Theater album anyway.

Radiohead is a good call, I don't get onboard until The Bends but from that point onwards everything is great or better.

Big Big Train’s run of albums, from The Underfall Yard has been very consistent too.

Without a doubt.......

XTC (not a bad lp imho)

Tull (a few clunkers here and there in later years)

King Crimson (Beat and Pair being hit or miss)

Led Zep (Coda being the exception)

The Beatles ( some 'filler' on White)

The Who (until 1980)

Wobbler (they only have 5 but are all very good)

Zappa &Mothers (up t0 the early 80's they are all good)

Beefheart (other than 2 duds in 1974)

The standard of the first seven albums is unimpeachable - not a single dud track on any of them, I'd say. I actually feel the same way about Two Against Nature though I know many don't (and the title track is the one I like the least). Everything Must Go is, I have to admit, a bit of a falling off.

Still, that run from 1972 to 1980, bloody hell.

Man I wish he'd been around longer. Vertible genius, and he would've just thrived in the 70s.

I love those first two albums. Barry Andrews brought it!!! Fripp paid attention...

King Crimson

Magenta

Thinking Plague

IZZ (if you exclude the Ampersand outtake albums)

Nexus

The Tangent

Anekdoten

I think I could come up with more, but there are so many bands where I haven't listened to their entire output it wouldn't be fair to add them.

How about the Moody Blues?  We don't discuss them much on PA at all, they seem to have consistently good output.  Thoughts? 

My personal favorite, Yes, have laid their share of rotten eggs over the years!!  

Renaissance were certainly consistently good throughout the seventies but they went off the boil in the eighties, which is probably not unrelated to all the line-up changes.

Certainly every album from 'Days of Future Passed' through to 'Seventh Sojourn' (and even the post-hiatus 'Octave') are all top quality. It's hard to think of one duff song, or filler track, on any of those releases.

Fair comment.

I disagree about Maiden. Great suite of albums in the 80s, but starting with the 90s not so much. The only album coming close to classic Maiden is Brave New World. 

I like Fear of the Dark, a bit uneven but listenable. I also like The X Factor. Virtual XI on the other hand is unlistenable to me, IM's weakest effort, to put it nicely. 

not a good analogy, B-movie does not refer to quality, but small budget back when people used to go to the movies to see a double feature, the main movie and a second (b) smaller budget movie. Also there are b-movies that were very well put together, with good story-telling.

Yes, you'd probably rate the last Nightwish higher than I did. For me it was a frustrating listen and I gave the album several chances because a lot of people praised it and I felt I was missing something .

I enjoy the albums with Tarja, those albums were quite unique, despite the band wearing their influences on their sleeves. 

It's been great watching Death and Gorguts climb our charts as of late. I haven't heard every Gorguts album yet myself, but I hear only good things!

Good shout! Nothing disposable there. 

It Bites

Cellar Darling (I know, 2 albums only, but they are fantastic!)

Ayreon (although Transitus is a bit of a dip...)

Iron Maiden 9/10

Killers 8/10

Number Of The Beast 10/10

Piece Of Mind 10/10

Powerslave 10/10

Somewhere In Time 9/10

Seventh Son Of A Seventh Son 9/10

Brave New World 8.5/10

Dance Of Death 9.5/10

A Matter Of Life And Death 9/10

The Final Frontier 8/10

Book Of Souls 7.5/10

The Dark Elf wrote: I think if you look at Jethro Tull from 1968 to 1980, they released consistently good to great albums every year, from This Was all the way to A. And with the release of the boxed sets that include numerous songs that never made it on studio releases, that makes that run all the more remarkable.

Hell yeah--   I might add the bonus cuts are extraordinarily good, many of which should've been on the original release or given an album of their own.   'Everything in Our Lives', 'Warchild Waltz', 'Saturation', 'Paradise Steakhouse', 'King Henrys Madrigal', 'Kelpie' ... and that's just a few.

mostly agree accept I've never heard the ones highlighted. Are they up to the same standard as the prog classics?

^ Yes and no---   This Was is mostly a blues album; Warchild is excellent but more song-oriented; it's been awhile, but as I recall Too Young has both good & bad moments;  and I haven't heard A since it came out .