Too late:
Pidgin - IM client (you can bring in AIM, Yahoo, GChat, etc. accounts into one central account manager)
Slack - Team communication tool, similar to other chat programs but gets everyone on the same platform
Mercurial - versioning (similar to git/cvs/svn/etc.)
ALM - Application Lifecycle Management (change requests, tasks, requirements, incident reports, etc.)
CodeBeamer - ALM tool (similar to Jira and the like)
Bitbucket - Like mercurial, git, etc.
SourceTree - software that lets you see all your commits/branches/etc.
Tortoise Workbench - similar to SourceTree, but for mercurial specifically