Those that know it still are using ggplot2 and R. This grammar of graphics plotting library really seems to gold standard of plotting.
That said, it would be cool if there was some kind of composer interface that would allow you to point-at/paste/import data, then save the visualization as a single page HTML snippet - like a small Tiddlywiki for data.
- https://github.com/mbostock/d3/wiki/CSV - http://tiddlywiki.com/
Actually it uses Taucharts under the hood.
Easy to import the data and allows you to visualize the information with various different chart types.