OK, I'll play. I dunno 'bout most *important*, but some I like a lot are:
"A seasoned witch could call you from the depths of your disgrace
And rearrange your liver to the solid mental grace.
And achieve it all with music that came quickly from afar,
Then taste the fruit of man recorded losing all against the hour"
-- Jon Anderson, Close To The Edge
(wtf?
nonsensical, but I love the imagery and vocal rhythm of it)
"Us, and them, and after all we're only ordinary men.
Me, and you. God only knows, it's not what we would choose to do.
Forward he cried, from the rear, and the front rank died.
And the generals sat and the lines on the map moved from side to side.
Black and blue, and who knows which is which and who is who.
Up and down, but in the end, it's only round and round.
Haven't you heard it's a battle of words, the poster bearer cried.
Listen son, said the man with the gun, there's room for you inside.
Down and out, it cant be helped, but there's a lot of it about.
With, without, and who'll deny it's what the fighting's all about?
Out of the way, it's a busy day, I've got things on my mind.
For want of the price of tea and a slice, the old man died."
-- Roger Waters, Us & Them
(nice how he plays with the echo AND says something poignant)
"As he stumbled on his ____.
He was delighted as it stiffened, and ripped right through his sock!
Oh, Saint Alphonzo would be proud of me!
He shouted down the block:
Dominus vobiscum, et cum spiritu tuo!
Won't you eat my sleazy pancakes just for saintly Alphonzo!?"
-- Frank Zappa, Father O'Blivion
(again with the vocal rhythm, and funny to boot!)
Maybe the Us & Them lyric could compete for most *important* prog lyric.