Wat Phu Tok is beautiful, mysterious and spectacular.  Few foreigners visit.  There are lovely lakes and a climb to the rickety buildings where the monks honour buddha and meditate.  The steps are difficult and you feel that some of the wooden pathways are about to collapse beneath you, but if you are adventurous enough to make the climb the rewards make it very worthwhile.  There are also waterfalls in the area. Click for more detail.