It is, isn't it? :3
I tried working with different wallpapers, and well...
So, here's what I found out:
Safebooru/Danbooru: Great for finding fanart, beware of using Danbooru and finding 16+ images, though.
Pixiv: Same as Safe/Danbooru, only you have to type in Japanese characters.
DeviantArt: Great place for Misc. Wallpapers :3
That's basically the gist of it XD