The Fantastic Four by Michael Golden

1991 - Fantastic Four #350 Original Art

By Walt Simonson and Al Milgrom

1989 - New Mutants #82 Original Art by Bret Blevins

Found these pieces over at: 

http://dchudson.blogspot.ca/2012/04/new-mutants-by-bret-blevins.html

Alpha Flight #1 page 24 by John Byrne

1985 - The Mighty Avengers #255 original art

 

1981 - Anatomy of a Splash Page - Miller's Amazing Spider-Man

Amazing Spider-Man Annaul #14 page 33.

I love the sound effect: SWOT!

http://www.comicartfans.com/lowrypiece.asp?piece=5780

1985 - Warlodzilla Will Crush All!

Splash page from Web Of Spider-Man Annual #2

1988 - Art Adams' Fantastic Four pin-up

From Marvel Fanfare #45.

1984 - New Mutants #18 Page 25

From the collection of Ferran Delgado (http://www.comicartfans.com/GalleryPiece.asp?Piece=382163&GSub=36618)

1982 - John Byrne's Silver Surfer

And here's another piece from that same era apparently for a poster, circa 1982:

http://www.albertmoy.com/GalleryPiece.asp?Piece=2014&ArtistId=503&Details=0&From=Room

Todd McFarlane's The Amazing Spider-Man #328 Cover Original Art Sells for $657,250.00

Wow, just wow. McFarlane's 1990 cover for Amazing Spider-Man #328 sold for $657,250.00 yesterday! I bet McFarlane wishes he had hung on to more of his original art! http://bit.ly/MJfogP 

1981 - Captain America #255 - Original Art

Here's seven lovely pencilled pages of John Byrne's retelling of Captain America's origin from Cap #225.
(http://www.comiclink.com/itemdetail.asp?back=%2Fsection%2Easp%3Fid%3D1398%26x%3D6%26y%3D1%26pg%3D5&id=907431)