Via WeblogTools Collection at WordPress Planet:

Here is a collection of high resolution wallpapers for folks with very normal to very large monitors. With resolutions of up to 2560×1600, including my default resolution of 1920×1200 (which can be very hard to find wallpapers for without streteching) the collections include a lot of high-res photo’s, as well as a few abstract art pieces.

I downloaded a couple and am currently using Feathers. Pretty.