A request driven set, inspired by dischead's comments, here is my 7th visit to 1972:
This was also a winner, tho' I never "got" Gentle Giant. The fact that they ended up in bed with Lee Abrams (the notorious radio consultant) and STILL couldn't get airplay made a lot of people I know very happy. 
What's to get? They're possibly the best prog rock band and probably the most talented.
I picked
River because in addition to being a personal fave it's also one of their most
accessible tracks. Rather than write about them myself, here are a few relevant passages
lifted from Wikipedia:
Gentle Giant were a British progressive rock band active between 1970 and 1980. The band
was known for its extreme complexity and sophistication of its music and for the varied musical
skills of its members. All of the band members, except Malcolm Mortimore, were
multi-instrumentalists.
[...]
Gentle Giant's music was considered complex even by progressive rock standards, drawing on a
broad swath of music including folk, soul, jazz, and classical music. Unlike many of their
progressive rock contemporaries, their classical influences ranged beyond the Romantic and
incorporated medieval, baroque, and modernist chamber music elements. The band also had a
taste for broad themes for their lyrics, drawing inspiration not only from personal experiences but
from philosophy and the works of both François Rabelais and R. D. Laing.
[...]
From the start, Gentle Giant was a particularly flexible band because of the exceptionally broad
musical skills of its members. One Gentle Giant album would list a total of forty-six instruments
in the musician credits -- all of which had been played by group members -- and five of the six
members sang, enabling the band to write and perform detailed vocal harmony and counterpoint.
The band's approach to songwriting was equally diverse, blending a wide variety of ideas and
influences whether they were considered commercial or otherwise.
It is the depth and complexity of their music that gives it the staying power for continued
enjoyment after repeated listenings over decades. How many times has some pop song been
played on 10@10, and someone here makes a comment to the effect that they don't need to
hear it again for X years? Yet I could play my Gentle Giant albums every day and it would
be weeks before I would tire of them.
It's like the difference between reading the Sunday New York Times and one of those free local
papers that cover high school sports and print the city council minutes. The difference in
vocabulary, sentence structure, and sophistication of ideas makes the latter disposible and
enables the writing of the former to remain interesting weeks or even months later.
