Depends on what you're doing. In my research the moment I'm working on difficult to access data or with new techniques, Python becomes the better tool immediately.
R is absolutely beautiful for manipulating small data sets. It's the only reasonable way to plot things (with d3/protovis coming in a distant second) and it's supercharged by Hadley Wickham's work. It's also totally crippled for "general purpose" programming and turns to C every time you need more speed.
R is absolutely beautiful for manipulating small data sets. It's the only reasonable way to plot things (with d3/protovis coming in a distant second) and it's supercharged by Hadley Wickham's work. It's also totally crippled for "general purpose" programming and turns to C every time you need more speed.