Theme by Joe Kidd (aka AverageJoe)
Another Friendship is Magic theme for every pony out there. This one is wallpaper-based with ten different backgrounds and a few custom icons as well. Also, this is an HD theme, so it may not display as desired on a 4:3 aspect ratio.
The icons where done by me, while credit for the wallpapers themselves goes to SmockHobbs over at DeviantArt.