I like to use different wallpaper in my pc. And like to change it frequently. When I open the pc it changes my mood.
Recently I found a site where I can get free Linux Wallpapers. It has different categories of wallpapers. Like abstracts, architecture, celebrities, fantasy, food, general, movie poster, nature, virtual etc. Picture qualities are great. I bet your desktop wallpapers will shine. If you are religious minded, then you can find Islamic wallpapers too. There you will find different mosques picture. In the month of Ramadan that will be great.
All pictures have different option to download according to your monitor size. Like
800 x 600
1024 x 768 (iPad)
1280 x 960
1280 x 1024
1280 x 800
1440 x 900
1600 x 1200
In facebook you can also find their updates. You can also share any of the pictures to facebook, myspace or twiter. Most of all you will love this site and its wallpapers.