Malaysia

I think Malaysia is probably my favourite of the south-east Asian countries. It is not as cheap as Thailand or Philippines. It is not as remote as Indonesia. But they look after their wildlife, and like Singapore, they are relatively nature orientated with well set up national parks. You also generally get left alone, and you are less likely to get hassled or ripped off.

The currency is the ringitt, and things are generally still cheap. For converting your currency to Malyasian ringitt...

One of my favourite national parks of all time, anywhere in the world, is found in peninsular Malaysia: Taman Negara National Park
The island of Borneo includes two states of Malaysia, Sarawak and Sabah. One of the best national parks there for wildlife viewing is Bako National Park.