Drop-shadows and gradients are two of the most common design elements on the web.
You’ll find them accompanying many different styles. They’re handy effects for web designers because they’re attractive, useful and easy to create with any graphics program. But they have a dark side: they’re frequently abused.
Using amateurish drop-shadows or gradients is almost as bad […]

More at: http://www.webdesignerdepot.com/2010/01/drop-shadows-and-gradients-be-consistent-in-your-visual-metaphors/