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

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, 1280 x 960, 1280 x 1024, 1400 x [...]

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.