I can't find the email where I said I would commit my "Show Page Shadow" option to the "Document Preferences" dialog. Anyhow, I added and tested it (I'm trying to make good on my backlog of promises). Now anyone may quickly set whether page shadow is on or off per-document via the "Document Preferences" dialog.
If you would like to make it permanent, you can change your local preferences.xml under namedview by adding the attribute:
showpageshadow="false"
However, if you have the default.svg located by default at /usr/local/share/templates/default.svg on *nix, then you must add the aforementioned setting in namedview. Took me moment to track down where that conflict between preferences.xml and default.svg occurred.
I think Jimmac and some others requested this and I don't like the cheesy "this is a document" page shadow either. Plus, it won't really be applicable when the documents are for animations, etc.
Jon
PS: Should I have made that atrribute "inkscape:showpageshadow" ??? I can change quickly if necessary.