More seriously, spending two or three days in Angkor is the minimum time one needs to visit the most important temples. Four to five days will allow you to visit more of the Angkor site temples but also to include a one day-trip to a far away site: Preah Vihear, Koh Ker, Preah Khan of Kampong Svay, Sambor Prei Kuk or Banteay Chhmar. If you are keen on visiting more than one of these far away sites, or on visiting a great number of the Angkor temples, a week will be perfect.