jqPlot is a jQuery plotting plugin which can generate very good looking line and bar charts.
The plugin offers various features like:
- different chart style options
- ability to rotate axis text & customize date axes
- tooltips, data point highlighting & more..
jqPlot itself has a plugin support too and it be extended with new chart types & options.
Almost every aspect of the charts created can be controlled like the background of the grid, show/hide ticks, font sizes/types & much more.
The plugin is very well-documented & provides very nice examples.