KNIME is not only about basic statistics but also about data-mining:
http://knime.org
It really is user-friendly and quite powerful in term of visualization. It is
released under the GPLv3. Here is my "review" of the basics of this platform:
http://homepages.dcc.ufmg.br/~lcerf/slides/mda10.pdf
A similar GPL platform that I mainly know by name is Orange:
http://orange.biolab.si
R is a full-featured language and, I agree, there is a learning curve. Anyway
you may want to use a GUI on top of it. Again, I am more into data-mining,
and I know of Rattle that you may like: http://rattle.togaware.com
