Saigon, Vietnam
Phnom Penh, Cambodia
Bali, Indonesia
Perhaps, if I were to leave SE Asia, I'd perhaps consider somewhere in Greece, Croatia, Northern India, or many even somewhere in the Caribbean like Jamaica.
For me it's a blend of cost of living and things to do. I come from a boring place so I like novelty and adventure and of course I don't want to spend too much.
I may answer differently if I were 65. I'd probably be happy to live in my home country then.