It seems that there are still some tools missing in this long list. What I really enjoy more and more is a version control system. Personally, I prefer git over other more centralized solutions like subversion. It has several nice advantages when you're using different computers (say a desktop in your office and a laptop on the train or so) for which you do not have always a reliable internet connection. With the de-centralized approach of git, this is no big problem, you can commit changes locally and merge things back globally at a later time.
I have by now made some nice experience with collaborators all over the globe using this...
