Thailand or Malaysia (or elsewhere?) at Christmas

[pilpiloni]

We're a family of 5 with kids who'll be 13, 10 and 2.5 when we travel.

We are looking to go for about 2.5 weeks and want a mixture of a few days of beach/pool, some nice (but easy for 2 year old) hikes (mountains or jungles), and just general exposure to a different culture (so temples, museums, food, and people in general etc). DH is a worrier so need fairly decent infrastructure and health facilities (I'd have gone for Sri Lanka!).

So we were thinking either Thailand or Malaysia. Any advice? Or original ideas?

Some suggestions
Combine Singapore with Malaysia - Singapore has excellent infrastructure and health facilities. Weather in Malaysian Borneo is not great in December, but not sure about the Peninsula
Thailand - beach, Bangkok and Chiang Mai in the north - Bangkok has some excellent hospitals!
Vietnam - Sapa in the north for trekking, Hanoi for museums, HCM mausoleum, great food, Halong Bay, Hoi An and then down to HCMCity.
Hong Kong - can be easily added into a trip to SE Asia
Cambodia - not for beaches but Siem Reap is amazing. Infrastructure is not too bad, excellent restaurants, lovely hotels and there is a decent hospital there.

Why have you ruled out Sri Lanka?

Sri Lanka not developed enough for DH. We were there 14 years ago and that's the picture he has in mind! Same reason Cambodia won't be an option either (I don't think Vietnam either)