If you're a fan of high resolution and high quality abstract wallpapers, then you have to check out
Color Theory 4 by Venom339.
It's a very large pack (240mb) containing 100 high resolution (2650x1600) wallpapers. Since the pack is so large, it is being offered as a torrent. Download the zip file from the deviation page and double-click the .torrent file if you already have a torrent application installed. If you're unfamiliar with torrents, there is an instruction file inside.
You can see a preview of the wallpapers
here (warning, it's a 5mb 1280x6200 image).
For other abstract wallpapers (in more manageable doses) check out the rest of Venom's
gallery.