I personaly use : trac - as a wiki + bugtracker , yammer - to communicate with other co-workers, jabber - priv communication google docs - schedule , time organization
Wide question.. Currently we use TWiki as wiki, DocuShare for documents sharing, ClearQuest for bug-tracking, Google Talk for communication, MS Project for project planning.
Personally, I use FreeMind as a kind of personal information manager, for decisions estimating, planning etc. Also I use MS Excel for planning.
We use MOSS 2007 for the document store / wiki / knowledge sharing side of things, MS Project for project planning, and a combination of both Windows Messenger and Yammer for internal communication blurbs.
Things are likely to change, however, as departmental budgets get cut more and more (even a semi-state company can feel the financial pinch). Here's hoping I'll be developing internal Web apps using RoR in six months!
At work we use Confluence as our team Wiki.
But personally, I use The Guide http://theguide.sourceforge.net/ to keep all my notes.
The Guide is a very simple Outliner which run entirely from a USB memory stick. And it's free.