The GTDInbox FireFox plugin is very cool!
I use GMail, Google Calendar, and Google Documents in my work flow, but one thing that I was missing was a good way to schedule fine grain work tasks as active actions, as something to look at in the future, completed actions, etc. Basically, a light weight Getting Things Done(tm) system.
I have just started to use GTDInbox to set up work tasks and track them. Tracked tasks show up as short text only GMails sent to yourself and as you would expect you can search on them, list in order, etc. I like GTDInbox because it basically stays out of my way until I need it, and if I have GMail open I can review tasks quickly. I like organizational tools that don't themselves take up a lot of my time.
This is a good writeup on using Emacs to organize work flow - good advice and information but I now only use Emacs for a few ours a day (just Common Lisp development, with some Ruby). In the late 1980s and 1990s I "lived" in Emacs all day long. Now, there are other specialized tools like IntelliJ, TextMate, and TexShop that work better for for me.