Now and then some of my students have been able to hack Excel to do good graphics. But for serious data analysis and publishable graphics, use a high-end statistics package such as Origin 6. read more
You do not have to try to become an expert and aim to write your own framework, but you should familiarize yourself enough so that you can do things like load in a data file, display the results and output those into a workable PDF that you can bring into Illustrator to continue finessing. read more