You can find an interesting collection of free textures at www.cgtextures.com. The textures are hi-res, interestng and divided into categories plus the site is easy to navigate. A great find. Enjoy
At Grungetextures.com you can find a growing collection of free for non-commercial use textures that show decaying surfaces, grungy photos and much more...
If you are a fan of wood backgrounds on websites or you just need a good wood texture, then this freebie from Design Reviver just might do the trick.
You can find a great collection of large scale textures at InObscuro.com. All images are sized 1024x768 px and are made of the author's own photos, drawings, brushes and patterns.
You can find great, hi-res textures at Texture King. It is a site that works as a a growing repository of high quality texture photos that are free for personal and professional use.
Here you can find a pretty nice and wide range of collected textures from wood to metal, fabrics, tech textures and more. The only catch is that some of the textures shown aren't too big, but other then that the collection is interesting.