With about 8% of men and 0.5% of women color-blind, what should I take into consideration when designing a GUI?
Well, the simple thing that comes to my mind is that you should not use only Color to encode a piece of information. A very good example is MS Word. It uses green colored wavy underline to show grammatical mistakes and red colored wavy underline to show spelling mistakes.
Having said that, in the real world the traffic signal systems in most contries use the red and green colors which reportedly are the one most confusing to the color-blind.