The 2012 results of the annual KDnuggets poll are in. It shows R in first place with 30.7% of users reporting having used it for a real project. Excel is almost as popular. It seems out of place among so many more capable packages, but Excel is a tool that almost everyone has and knows how to use.
It’s interesting to note that four of the top five packages used were open source. While open source packages are clearly playing a major role in analytics, people still reported using more commercial software (1086) than open source (927).
For many other ways to measure analytic software popularity, see The Popularity of Data Analysis Software. I’ve just added this graph to that article.