Making multiple panel graphs, boxplots, plots with error bars, heatmaps etc. Very useful for quickly summarising large amounts of data.
In research, a lot of people spend a lot of time adjusting figure margins and title sizes etc. I want to save them time by giving them something that just works.
Applying the same graph theme or formatting to a batch of data files. I'm trying to bring the power of R scripting to the masses who do not have any interest in learning programming.
A lot of people, such as PR and marketing firms, specifically don't want to use Excel to make charts. They use nicer looking alternatives (mostly Flash based solutions). I am making a simple web-version for them.
Those are some examples, there are more.