I while back, I wrote about Hamad Darwish and the high-quality Windows Vista wallpapers he had made, both those that are included with the OS and many more that are similar but not included with Vista. (You can find the complete collection here.)
But wait, there's more.
It turns out that some of the wallpaper images included with Vista were from Microsoft employees. And one of them, Mike Swanson, has made a great collection of wallpapers available, including a couple that are in fact included with Vista. They're all available in 1920 x 1200 and 1600 x 1200 sizes, which should fit the bill for virtually anyone. And they're beautiful.
Check 'em out, and enjoy.