I think the calculated field option is probably the best way to go and yet still retain a clearly traceable audit of where the 'value' comes from. A specific field is much more evident than, say, a setting in a field definition. It seems to me that the recent focus on being able to audit anything and everything lends weight to this view but I can accept that others may disagree.
You don't mention whether you were using 5 standard or Pro but I assume the values, blank or otherwise are coming from a report.
On a more general note the information about what settings are stored and where (plus a few hidden values for those with the options to edit their registry) can be found in the Help file. Search for 'Settings'. Quite interesting and potentially useful.