What I do is type something I want to see, then go to advanced options, and change the results to only be larger than 920 width, or make the results only show up 1920x1080.
4walled.org has amazing backgrounds. Make sure you turn on SFW because there is a lot of HD porn on there, too. I usually search "pattern" and you come up with a lot of simple, sleek wallpapers.
Hey!
Go to DeviantArt, search "Wallpapers" and viola!
stolen from Tirin<3
Sweet sally in the ally
Just find some images you like.. then set them as your wallpaper!
Here is a small portion of my Wallpaper Archives, feel free to check them out.
http://s1089.photobucket.com/albums/i358/USDMcat/1080p plus Wallpaper/
http://s1089.photobucket.com/albums/i358/USDMcat/Wallpapers/The Universe/
http://s1089.photobucket.com/albums/i358/USDMcat/Wallpapers/
http://s1089.photobucket.com/albums/i358/USDMcat/Wallpapers/Gaming Wallpapers/
http://s1089.photobucket.com/albums/i358/USDMcat/Wallpapers/Jeniffer Aniston/
Keep in mind, Photobucket will drop Resolution on just about all photos.
Looking for new Wallpapers? Here's my collection of 588+ HD Wallpapers http://www.minecraftforum.net/topic/932258-my-collection-of-the-best-high-resolution-wallpapers/page__gopid__11840416#entry11840416