I'm working on a school project for which I've been given the following scenario and task:

Scenario - You work for a small oil field servicing company and most of the proposals, reports, and other documents your company produces are collaboratively authored. The current collaborative writing process involves e-mailing documents back and forth among employees and creates the challenge of trying to keep track of different versions of the documents. At a recent conference, your CEO, Sherry Martin, heard about how some other companies are using wikis for collaborative writing. However, she doesn’t know much about wikis and has asked you to investigate this tool for potential use for collaborative writing in your company.

Your task – Your task is to research wikis and to write a memo to your CEO recommending whether your company should adopt a wiki for internal use in producing collaboratively written documents. If you recommend the use of a wiki, your memo should state explicitly which wiki you recommend. In your memo, you should address issues such as cost, security (confidential-ity) of information, employee access, ease of use, and potential need for employee training.

I was wondering if someone could provide me with insite on the best wiki for use in this type of application?

Any suggestion are greatly appreciated.

Thank you :-)