Do you remember the time when you switched from graphical statistical software to R? I did it eight years ago, and I had hard time doing even a simple regression analysis without constantly searching for help, it was a pain. In desperation I frequently cheated and went back to Statistica for the familiar window-ish feeling. But my skills developed, and with my first 'for loop' came the first euphoria, it was liberating. I no longer had to follow the predefined structures, I could juggle with my data, explore, play, create.
I think that this is the kind of experience that many R users had at some point.
A couple of year ago I started to notice that some R users (including myself) got so proficient and comfortable with R that they started to do almost everything in it, from file manipulations, to web downloads, complex analyses, graphics editing, presentations and report writing. It's as if R is another operating system running on top of Windows, but it's more useful – unlike Windows, everything has a common structure, it's free, open, and everything can be used as a building part of something else. All work can be scripted and revoked any time, and there is the huge R community constantly working on a vast selection of R packages.
Now here is a secret: There is a real operating system that was here long before R, and it has all of the properties above that make R so awesome. In fact, R sort of copycats the structure of it, and adopts some of its syntax. Imagine that you get the same empowering feeling that R gives, but now you get it from the operating system itself, and from all of the software that you have on it: everything is a package, everything is free, well documented, open, and 'scriptable'.
I believe that if you are comfortable with R and it liberates you, and yet you still dwell in Windows, then it's likely that you will be liberated by the operating system that I have in mind. And after the obligatory bumpy start, you will look back at Windows with the same sentiment as you, the R user, look back at the graphical statistical software. And you will wonder: Bloody hell, I used to use THAT?
The system that I have in mind is Linux. It goes really nicely with R.