Essential tools for the worldwide office

If you're collaborating with a large team Lifehacker has listed a number of tools that will help your team accomplish its goals and tasks quickly and effeciently.
Brian and I have pretty much set up a 24/7 radio station online with MSN messenger, e-mail and VNC Server/Viewer and other than initial setup, I don't think either of us have stepped into the office that the station is run out of in Fort Worth.
It's all technology folks. Amazing technology.
But for your team, here are some other great tools (several of which I've used) to help your team work effeciently.

Group chat meetings - Campfire

Internal knowledgebase - MediaWiki

E-mail - Gmail

Vacation and other scheduling - Google Calendar

Document collaboration - Writely, I mean, Google Docs
Read the full list and software descriptions.