1. Embossing your logo or key language
http://www.powerybase.com/bills/
2. Simplicity
http://www.rekn.it/
3. Bold message
http://ok.cogaoke.com/
4. Soft Gradients
http://www.stcharlesmd.com/
5.Texture, which can be combined with your gradients.
http://www.vegasuncorked.com/
Color inspiration
http://colorschemedesigner.com