Life is easy in Guernsey, almost as easy to take as Guerney cream. That's because this small bastion of Britian just nine miles off the coast of France is a tax haven. Guersney has been British since 1066, when William the Conqueror took over England. But the island never relinquished its status as a bailiwick of the British monarch. Hence, no taxes. In St. Peter's Port, see the Cornet--a 13th century castle guarding the harbor.