If you want a truly awe inspiring song that you'll never have heard of in the english speaking world:
Ah, te vi entre las luces. (Ah, I saw you amidst the lights).
This is an 11 minute epic is by an Argentinian 70's band called "La Maquina De Hacer Pajaros" ("The Bird-Making Machine.").
Since there is no place where you could possibly sample their AMAZING music, check them out at this guy's blog: http://therevengeofthefools.blogspot.com/2008/01/la-maquina-de-hacer-pajaros-la-maquina.html" You can get the album where the song is.
And there is a song from each of their albums streaming at prog archives:
http://www.progarchives.com/artist.asp?id=815.
Their first album (and the last album, "Instituciones," from Charly Garcia's previous band "Sui Generis") is absolutely amazing (and, IMHO infinitely better than their second album; and had it been recorded by an english band, it would have unquestionably found its righteous place in any list amongst the great classics of 20th century rock). I'm sure when you hear it you'll want to get your hands on a hard copy of both right away (or else you suck and have no taste

).
Then in the 80's he went crazy and his music stopped being good.
But seriously, Ah, te vi entre las luces: check it out it'll blow your brains out. That whole first self titled album will actually.
Lyrics:
Nadie habla en la sala,
nadie de pie.
¿Estás lista para viajar?
¿Estás lista para venir?
Está bien, está bien, está bien...
Estás sentada en el aire.
Nada de luz esperando que marquen tres,
esperando verme otra vez
Está bien, está bien, está bien...
Ah! Te vi entre las luces
con tu cara toda azul...
My attempt at a sensical translation:
Nobody speaks in that room
Nobody stands
Are you ready to travel?
Are you ready to come?
It's OK, it's OK, it's Ok...
It's OK; you are
Sitting on the air, no light
Waiting for them to mark three
Waiting to see me again
It's ok, it's ok, it's ok...
Ah! I saw you amidst the lights!
With your face all blue...