I've been having colour balance and picture problems since forever so following some helpful advice I've tried to see what impact different colour backgrounds have on the final result of my pics.

I used 2x 50W white halogen lamps (£10 each from Homebase (UK)) and a selection of coloured backgrounds. I have a 3.2MP olympus and applied auto colour balance in GIMP.

From left to right the backgrounds are:
top row
White
Grey
Grey with a black and white colour reference
bottom row
Blue marbled card
Grey marbled card
Blue

I'm amazed at the difference this made. I hope this is of some use to you folks!