Noooooo, not R!!!!
I've recently been touch in inappropriate ways by R
...
Also, don't use R.
I actually offered a college course on data visualization with R this spring. (Didn't get enough signups to go ahead with it though, so the minds of the young were spared this time.)
It's not for everybody, but it's got some very neat features and lots of packages are available if you're into data analytics and visualizations.
I've used it to program computer simulations for research papers, and it worked well enough to get my dissertation committee to sign off on my doctorate, but it seems to eat memory or slow down for some arbitrary reason when you do a lot of repetitions, so it's not the best tool and I'm looking into Python now.