Using D3 to draw plots and other data visualizations is really golden. Next to other good plotting libraries (such as ggplot2) having SVG as my canvas really gives me the feeling that I can do everything that I want.
Its good if you need dynamic charts in JS but if you just want a graphic or a logo I wouldn't use it. Its also a huge pain to maintain, they update the library once a year with breaking changes and then it takes me a day or 2 to work out how the old version worked, how the new one works and how to move all my graphics over.