Allen,
As you posted in the .programming group I thought that
you were looking for a VBA solution.
Seeing as your not, in re-evaluating your question, there
isn't a defualt, per se, for that option nor is there a way
to set it.
This is one of those "Bill is infinitely smarter than you and He
'knows' what you want to do better than you do" type of
features. Excel isn't too bad, but the ones in Word can be
very difficult to get around.
Anyway, when you try to do a sort, Excel evaluates the range that
you're trying to sort. If the top row (or even the row above the
selected range) is formatted differently from the rest of the range,
Excel will "assume" a header row and set it as a "default". If it's
not formatted differently and doesn't "look" like it might somehow
be a header row, Excel will assume that it isn't.
John