In my ideal parenting world my three children (two boys and a girl) would be colour-blind when it comes to the toys they play with. Any toy, regardless of the colour of the box it comes in, and regardless of the child it is marketed to, would be welcomed as a toy to be played with.
While my husband and I usually agree on how we parent our children, we don't agree on this issue. My husband, while liberal on everything else, is extremely old school when it comes to the toys that boys and girls should play with.
If it comes in a pink box and wears a dress or silver tiara then it is quite obviously a girl's toy. If it comes in a khaki-coloured box, and is essentially a piece of plastic shaped into the form of a weapon of some kind, then it is for boys only.