In the life science space, R dominates research informatics. A large chunk of molecular profiling methods and techniques use R, or quite often the Bioconductor package, http://www.bioconductor.org/ (from Gentleman's group). Most commercial bioinformatics apps also implement a number of methods using R and provide ability to implement R-based classifiers, etc.

In the clinical space, it's all SAS. Pretty much the de facto standard.