I’ve seen a couple plugins along the way… but I think they all struggle in one form or another. Honestly, I think the best way to present charts is by creating them in photoshop (or equivalent) and save as an image file. Then, just insert the image in your content area.
The only downside is that the chart won’t be interactive.
I know there is a tinymce plugin for adding charts. But I haven’t been able to play around with it too much. I’d like to eventually include it in my plugin, but I just haven’t gotten around to it.
Other than that… here is a link to the search on wordpress plugins for “chart”:
http://wordpress.org/extend/plugins/search.php?q=chart