Fractals
http://www.stevetruett.com/wallpaperpages/wallpaper_home.html

Various
http://www.plasmadesign.co.uk/widescreenabstract.htm
http://interfacelift.com/wallpaper/
http://macdesktops.com/
http://rampant-mac.com/wp/
http://www.veer.com/ideas/wallpaper/
http://www.graffitiwallpaper.com/index.php?cat=1
http://mandolux.com/
http://wallpapers.mymyah.com/
http://wallpaperstock.net/wallpapers_1920x1200r.html
http://wallpapers.net/1920x1200-wide-wallpapers-r