Beauty and Multi-media
Search Engine Optimization
Intuitive navigation, user friendliness
Web Design aint what is used to be
Here is one more concern to address and incorporate
it appears that the Eyes are intuitively geared towards viewing certain types of Images and Layouts more thoroughly than others.
This is important not only in Web Design but in Pay Per Clicks
These articles offer a wealth of information about some experiments think you will find them extremely helpful