 <p>One possiblitiy is to construct your colours from <a href="http://stackoverflow.com/questions/2942/hsl-in-net">HSL or HSV</a>, keeping the SL/SV part fixed you can divide the entire hue range into the number of pie slices you have, this should ensure they are reasonably visually seperated. different SL/SV values will make the chart vibrant colours or pastels or dark shades etc. </p>