Textures can be a great way to give your design an “organic” look, or just the right amount of complexity.
I recently discovered the site Outside the Fray , which is a really nice resource for a variety of textures. The author, Brent, will post a set of textures and say where the texture is from (he mentions that he captured these cardboard textures in a trash pile in a local supermarket). He is a self-proclaimed “texture fanatic”.
The best part is that both of these texture sites provide completely free, high-resolution images. Enjoy!