Google ChartTool is an easy way to create nice looking charts. You can choose to start from an example chart or import a chart from a URL. There are several different charts that users can choose from (see image below to see all the options). It seems to have a very simple user interface, something that many excel users complain about when wanting to create a simple chart.
You can easily select the data for each axis and title them as well. You can choose how to fill each data set in the charts as well. Once you are finished you can link to the chart in an email or even get an embed code for a website or blog. Be a great way to have students discuss charts, because charts are ALWAYS on Standardized Test across every state.
Looking for an easy to use web-based chart tool, Google ChartTool might just be what you need to fill that void.