[R] Three most useful R package

[Ralf B]

Hi R-fans,

I would like put out a question to all R users on this list and hope
it will create some feedback and discussion.

1) What are your 3 most useful R package? and

2) What R package do you still miss and why do you think it would make
a useful addition?

Pulling answers together for these questions will serve as a guide for
new users and help people who just want to get a hint where to look
first. Happy replying!

Best,
Ralf