The Area edit bars in 4.5 Sprint III are currently colored light blue. I'd like to reserve this color for selected elements in Magnolia 5, because a) it's a commonly used color for marking selections and b) it sticks out pretty well even in colorful surroundings.
I'd like to use either the bright orange (#FFBF28) or the dampened dark red (#9A3332) for coloring areas; both colors are from our corporate colors.
The orange has a similar attention grabbing quality, the dark red is a bit more classy. In the past, red has also been used for area edit bars by the SiteDesigner module.