As mentioned above, it is in the eye of the beholder! (You, that is!) Locally, if you have to drive more than 2-3 miles to the store, doctor, Wally World, etc. and have no city services, i.e. water,sewer and most of the neighbors cannot be seen from your house, then I call it rural. There are little communities, however, with platted subidisivions that are located at least 10 miles or so from town and I typicall consider them suburban, as the true "rural" experience is not felt :roll:
Usually with these little communities there should be a pretty active resale market and I don't have to go more than a mile or two for a comp.
I have heard appraisers say that if there is a house within a mile then they call it suburban. Methinks they are trying to please a lender.