Tony,
Will your file management functionality include change management and version control?
There is a strong need for Intranet applications to store latest versions of various files - documentation, presentations and even programs. But also have full versioning control and diff mangement or manage multiple versioning history. Also to include change mgmt history (date, time, user/owner with comments), searchable fields ...
How far are you planning on taking the file management functionality?
Blaine