[R] What are the good tools for professional R developers?

[Mark Alen]

I am trying to make this transition from a casual R programmer to a professional programmer (trying to make money with R)

What tools should a professional R developer have?

what are the good utilities that can help R developers to code and debug more efficiently? what type of tools are missing? For example, what are the good IDEs, unit testing and code coverage tools, debugging packages and maybe UML modeling tools for R?

What tools do you have in your R toolbox?

I am also interested in knowing the tools that exist for other languages but are missing for R development.

Thanks a lot
Mark