Yihui Xie is the creator of several popular R packages, including knitr, animation and cranvas. In an interview with The Setup, he shares some of the software and hardware he uses in his data-to-day work, including (of course) R:
For programming and data analysis, I primarily use R since I'm a statistician. I have created a bunch of R packages including animation, knitr, formatR, Rd2roxygen, R2SWF, fun and cranvas, etc. I use other R packages like ggplot2, gWidgets, roxygen2, Shiny and XML. Emacs was my editor before I switched to RStudio; for small tasks, I just use the default editor gedit. I also use sed, awk, grep and shell scripts frequently.
(Data Scientist John Myles White gave a similar interview back in July.) Yihui's interview also includes the above photo of him sporting a Revolution Analytics "I ♥ R" T-shirt — if you'd like one of your own, check with your local R user group!