Need to create a quick bar chart or pie diagram to mail it to a friend? Why not do it online? Before this online-application craziness took over, everything we did on our computer, we did it with applications installed on our own PCs. For years, I have been using Excel to create charts. Now with web services like ChartGizmo available, creating charts is a breeze. Not that it was any harder doing it with Excel, but it's definitely quicker.
ChartGizmo is absolutely free (but requires registration) and allows you to create various kinds of diagrams: Pie, Bar, Line, Ring, 3D Pie, 3D Bar, 3D Line, Scatter Plot etc. You can either manually enter the data or import it from an Excel sheet. Now you can't actually upload an Excel file, just select and copy the data and paste it into the data window. The charts are all customizable - everything from colors, to labels, chart orientation and sizes. A window on the right gives a live preview of the diagram even before you save it.
An example Pie-Chart showing browser usage trend among visitors to this site. The same data presented as a 3D bar diagram below.