Steampunk Wallpaper is awesome. I just saw this on Boing Boing.I love the firefox logo with the stitching on it.Check it out.

MacDesktops hosts hundreds of great Hi-Res wallpaper in dozens of Categories.
Hours of browsing fun here. I love the My preferences settings to show you just the sizes that you need. Great feature!

The National Archives Experience website has super high resolution images of the Declaration of Independance, The Constitution of the United States, The Bill of Rights and all of the Amendments. They are interesting texturally as well as historically.

I was looking for an image on google image search this morning and found that they had added huge image searchThanks google!

If you are looking for a dual monitor wallpaper (2560×1024) in one of the following categories then dualmonitorbackgrounds.com is the site to see.

Abstract

Animal

Astronomy

Celebrities

Computers

Crafted Nature

Gaming

Industrial

Macabre

Microscopic

Mobile Technology

Music

Nature

Popular Culture

Science Fiction

Sports

Vehicles

3dfiction hosts several futuristic monochromatic designs in xga, sxga and wxga formats.
Don’t miss the DVD with some of the designs in motion.
They also feature easy insert code for adding the images as background in MySpace.

wallpapers (1024×768 minimum) is the mother load of high res flickr groups. It is chock full of images tagged with wallpaper at a minimum resolution of 1024×768. 36,669 images and counting. This will take a while to go through.

Professional Wallpapers hosts a few HD images in a number of different formats. including 2560×1600, dual monitor, HDTV and PSP/iPod formats. Nice work.

desktopography is an exibition, a showcase of nature themed desktop wallpapers created by designers worldwide.
This site is awesome! great visuals and great music! Lots of great, hi def and large format wall paper and all around great design. Check them out.