Anyone have any nifty methods for creating nice looking charts and graphs dynamically on the web?

I'm currently using .png files created in Photoshop that I stretch via the width element to the desired size based on a variable.

I have some data I'd like to plot using a line graph but I haven't liked what I saw so far. Google has an option but they have some weird size restrictions.

I also found this http://www.r-project.org which seems a bit much for what I want but I may end up having a back end script that generates an image from a data set.

I'm hoping people much smarter than I have a better idea.