Southeast Asia has beautiful tropical countries...
some western tourists that I know always take a tour to Southeast Asia they are not only in one country. landing in Thailand then flying to the Philippines then to Indonesia then returning via Singapore is an experience that will not be forgotten.
Not only about those you mentioned but also about the Hospitality of countries from this region.
And put into account the cheapest way for travelling in this countries where the Food is extra ordinary but very cheap,we can check all of those in travel and tour shows proving South East Asian country is one of the best to go with.