Using R
papaf: I've been using R for 4 years to analyse microarrays and to do nonlinear time series analysis on signals.I'm using nonstandard methods based on my own code, third party command line programs and extensions I wrote in 'C'. I chose R over Matlab or Octave because it has a more powerful programming language and a nice time series datastructure.Despite doing very little statistics for the last 2 years I'm still very happy with R. People I know who use Matlab tell me they only do it for the available libraries.