Tools for Collaboration

Assistly - Customer Service Tool with great features for collaboration
Confluence - Enterprise standard wiki for a very low cost ($10 for 10 users) but $600 for 25 users.
Jira - Enterprise standard ticket logging system that we use for project management and capturing all data.
Google Mail - Cloud mail means less worry about having to download mail to ur laptop etc and having to worry about deleting mail
Google Talk - Chat tool that we use internally to communicate
Skype - You need this if you're going to be working with people overseas