It is interesting to read about some of the research done on how people visually scan pages. Generally it is agreed that people visually start at the 10 o'clock position and than move in a clockwise direction to 2 o'clock, 5, 6, 8, 9 and then back to the 10 o'clock position. This would obviously indicate that when designing pages for ypur web site the most important features/actions within each page should be at the 10 to 2 o'clock positions. See my diagram below and than imagine how this would work on your web pages.