John Hunter, creator of MatPlotlib, originally designed it’s color scheme to be familiar to Matlab users. As it turns out, the color scheme works well for publication material but doesn't work so great for viewing visualizations on the web.

I find the default styling for graphs produced using ggplot2 aesthetically pleasing for this purpose, so I spent some time over the weekend to refine the default colors and settings for my matplotlib installation. The result of this work is embodied in this .matplotlibrc color theme file. If you want graphs that look like the ones below by default, download it and place the file under ~/.matplotlib/matplotlibrc.