IMO, You must study the market. Do homework on what niches work for what areas. Viz, Nobody would sell icecream in a place like Alaska. I have seen many domainers hand-regging domains for multiple regions on niches like lawyers, locksmiths, flowers, plumbers. The basic niches like housing, insurance, have all been taken pre-2008. Geo domains -> nGTLDs. Now, you can even buy <city>.<realty>