This is an interesting article I found that shows how to mix and match cabinet materials, finishes, and color to make a more interesting look.
HGTV – They feature a nice slideshow gallery of photos which show a variety of cabinet styles and hardware. They also encourage you to mix up your hardware choices if the feeling strikes you.
The Inspired Room – The author of this post said that she and her husband couldn’t wait to put their own mark on their first home. They chose to change their kitchen cabinet knobs and pulls for an easy and inexpensive makeover.
Apartment Therapy – Keep a few things in mind when shopping for new cabinet/furniture hardware: Usability/Function, Size, Price Point, Replacement, and Timeline.
My own post on Houzz.com