Here is a nice list of the best sites and communities to download high quality definition wallpapers for free:
Wallpapr
Vladstudio
Social wallpapering
Desktopography
Fotocommunity
Credits to: Superkawa
Wallpapers.net
Wallpaperstock
Wall or not
Hintergrundbuilder.cc
Wallpaper search
Wallpaper Free
HQ-wallpapers
HQwalls.net
WallpaperFX
