"Remove personal information" default save in Office for Mac 2011?
The best way I can see of doing this is to modify or create a new blank template with the setting baked in. 


File -> New From Template -> Blank
Document 
Make Privacy changes as
before
Save as Word Template (This will normally appear under my Templates, but I presume you could overwrite the existing Blank template, wherever it is located).
Then when creating a new document, use the new template you created.


Jonathan