" What is the documentation which you have found yourself doing most...or which is most important to your role?"

Gathering Requirements and translating them for the developers and checking up to see if there are problems / obstacles they are having.

 If the user, product requirements are not complete and accurate ... then all else won't be right or even rejected.

"If you were a contractor are there any templates which you would use no matter which role you were in?"

I use what the company already has in their Project Management Office (PMO) ... that way it is in a standard format they already know.

If they don't have anything at all ... I use templates from my toolbox that I have gathered over the years and start a Project Management Office (PMO) where these templates can be acquired by others for future use.

The PMO is a source of documentation, guidance and metrics ... it could be an office room or a folder on a network hard disk for others to access the templates.

"That's interesting and useful.  Would you be able to expand on what docoumentation your toolbox consists of, in the absence of a company having an existing PMO"

 I have a directory with about 1975 documentation examples ... including Viso flow charts, Excel calculations, MS roject , power point presentations , case studies, project charters, SWOT, Change Management, Business Rules, Functional Documents, developer work packages,  etc.

It is a mixture of Project Manager, Business Analyst, Developer stuff ...

This was an example of a Developer Work-Package, steps for the programmer and Traceability.