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

Desktop Pictures hosts a lot of great images in the following categories.

Scenic
Florida Beaches
Abstract
Clouds
Flowers
Colorful Leaves
Haiku Letters
Black and White
Expressive Leaves
Holidays

Many are available in 1152 x 768, 1152 x 864, 1152 x 870, 1280 x 800, 1280 x 854, [...]

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.