One of my favourite websites that helps be look at colour palettes is Kuler. I think I would like to go with fairly neutral colours for the overall feel of the look book. However, showing such a vast array of colours within certain brands will mean I have to be versatile with my palette.
Brighter/darker colours can be brought in rotationally throughout different seasons. Pink and green pastels would work well for spring. Darker pastels like purples, browns and blues would work well for the colder months.