Some favs:

King Crimson - Starless

http://www.youtube.com/watch?v=unLarWq7bFY

van der Graaf Generator - A Plague of Lighthouse Keepers

http://www.youtube.com/watch?v=TlBuSZMnxo4

Led Zeppelin - The Wanton Song

http://www.youtube.com/watch?v=L1PoxTp7jIM&feature=related

Yes' Relayer album

Miles Davis' stuff, especially Jack Johnson, Get Up With It, and Agharta

Weather Report (Tailspinnin', Black Market, and Heavy Weather)

The first two Mahavishnu Orchestra albums

Bill Bruford's "One of a Kind"

Genesis' "Selling England By the Pound"

All of Steely Dan's work

Van Halen I and II

Chic and C'est Chic

Seals and Crofts' "Antoinette"

New Grass Revival's Commonwealth album

The debut from Pat Metheny Group

Thin Lizzy's Jailbreak

Quadrophenia and Who's Next (but I don't like Tommy)

Aerosmith's Toys In the Attic and Rocks

Boz's Silk Degrees (Jeff Porcaro was awesome)

Joni Mitchell's run from Hissing of Sumer Lawns through Don Juan's Reckless Daughter

Pink Floyd's Animals (especially Dogs)

I was too young to be much into album covers from the era - discovered many of these in the 80's and 90's.