White space reduces cognitive load
White space is the preferred method for grouping
Preserve your white space
Semantic Zoom - RTS games have been doing this type of thing for a while
Fear of empty spaces - "Screen real estate is valuable" fallacy
Non-traditional navigation patterns - http://billyhollis.com/
Check out the Design Resources Corner
"The Design of Everyday Things" - Donald Norman
"Universal Principles of Design" - William Lidwell et.al.
"A Whole New Mind" - Daniel Pink
"Sketching User Experiences" - Bill Buxton
"Drawing on the Right Side of the Brain" - Betty Edwards
"Designing with the Mind in Mind" - Jeff Johnson
"About Face: The Essentials of Interaction Design" - Alan Cooper
UI Patterns site on Yahoo (oriented around HTML UI instead of XAML. but still a good resource)
Quince UI Patterns site (sponsored by Infragistics)
In nature there is almost no monochrome, a lot due to lighting effects. Lighter part of gradient on top (light comes from overhead) - top down lighting bias. Can use a dark on top for contrast.
Think of how creepy a face looks when telling ghost stories around a campfire when lit from below.
Gradients should not be noticed.
People may have a difficult time verbalizing why they like something based on the natural principles, usually because they like them due to unconscious reasons.
Because of our evolutionary history, people unconsciously prefer natural things in many contexts
lushness, open spaces, and gradient lighting
There are exceptions where other design principles override the preference for naturalness