Richard
This is a "How long is a piece of string" question.
There are so many variables, eg.
What level of user do you need
What type of work is it
what is the main use of Excel

Each one of these would have it's own questions !!

I'd suggest sitting down with the dept that needs the user and see what they
acutally do with Excel and develop a series of questions from there.

HTH
Michael M