Originally Posted by
Michael
For temples, it's hard (if not impossible) to beat Angkor Wat and the other temples near Siem Reap, Cambodia. I would recommend at least 3 full days (i.e., not including travel days) in Siem Reap; there are flights from a number of places around the region, including low cost carriers (AirAsia, JetStar) if price is a concern.
Though for 3 days in Siem Reap, you really have to enjoy temples! I spent one full day in and around Angkor Wat and some of the surrounding temples and felt like I saw quite a bit. They really are amazing but your kids may be "templed out" after that.
As others have noted, 20 days in Singapore is far, far too long. It's a shopping mall disguised as a country; 2-3 days is plenty. Spend the vast majority of your time exploring SE Asia. Kota Kinabalu, Malaysia is worth a trip IMHO; you can climb Mount Kinabalu, which is supposedly a relatively easy climb (really regret not doing that when I went).