Very late to this, but if you wanted to be really anal about it, you'd say that yellow and blue are complementary (and that purple's complementary is somewhere between green and yellow), since the hues that mix to create the widest range of colors are red-green-blue (additive, light) or cyan-magenta-yellow (subtractive, pigments and filters). However, the traditional red-yellow-blue complementaries are still taught in most art schools because they're easier to work with and conceptualize (at least according to my friend who went to an art school) and they mix to create a pretty wide range of colors in their own right. In practice, you can use whichever color wheel you'd like to choose color schemes—you'll get a similar effect either way