Theme based on Few's "Practical Rules for Using Color in Charts"

dsamp <- diamonds[sample(nrow(diamonds), 1000), ]
(qplot(carat, price, data=dsamp, colour=clarity)
+ theme_few()
+ scale_colour_few())

(qplot(carat, price, data=dsamp, colour=clarity)
+ theme_few()
+ scale_colour_few("dark"))

(ggplot(diamonds, aes(clarity, fill=cut))
+ geom_bar()
+ theme_few()
+ scale_fill_few("light"))