Gill Cleeren wrote an interesting article about Styles and Triggers in WPF:
In this article, Gill Cleeren focuses on the aspect of styles and triggers in Windows Presenation Foundation. Styles make it possible to create applications with a uniform look and with a high level of maintainability. Triggers allow WPF styles to change one or more properties in response of a user interaction. In this document, we will use both these technologies to create a richer user experience.
Read the article on MSDN.