It depends on the situation. I use a modified version of each. I use Google Spreadsheets now with the online form creation for easy q&a development. I can make a form and the system autopopulates the spreadsheet. This is quite simple and I am in the process of training all support staff in our district on how to use it. It is the hit of the summer here.
I use Google documents for the staff I work with now as well. We have several document discussions taking place on topics where I want us to develop some ideas. I would like to introduce them to online wikis but I know there is a fear of sharing their thoughts with the rest of the world. I am helping develop us as a more transparent department. Working on the work as they say.
I guess it really depends on the flexibility of the people you work with. One thing I find that works is to use the tools and then open a dialogue with all involved to discuss the tools and the faults in them. We don’t want to use these online tools for holding student information because of security issues. So, we keep a running dialogue on the usefulness of all the tools.
I do see us needing to move away from software running on each computer. I appreciate the usefulness of Google Docs, Wikis, and sites like Diigo where we can share and annotate on each other’s work.