National service is compulsory for Singapore citizens and second-generation permanent residents who have reached the age of 18 to enroll in the military. Thereafter there's in-camp training of up to 40 days up to age 40 and 45 for non-officers and officers respectively.

I am an american from NYC living in Hong Kong. I would only consider HK, Singapore or Tokyo. I find Vietnam & Bangkok way too chaotic, polluted, and crowded. I just couldn't imagine crossing streets in Vietnam every day!

1) The airport and access to it in HK is great. 20 minutes from central, and when you come back to HK your Hong Kong ID gets you through immigration.

2)Saftey - HK, Singapore & tokyo are extremely safe, crime rates lower than the US. I feel much safer and less threatened here than I did in NYC. Jakarta and Manila are not safe. If you moved to Jakarta you'd live in an expat compound.

3) Cost of living - in HK rents are high but otherwise cost of living is similiar to NYC. Food, if you like expat food from City Super, is more expensive, but overall you can buy meat/vegetables/bread very reasonably. You don't need a car, taxis and public transport are very cheap and convenient.

4) local language - as for Hong Kong, on HK island most people know *some* english. There are still plenty of taxi drivers (15%?) who don't speak english. But, if you plan to learn very basic cantonese, you should be fine. I am learning Mandarin Chinese here in HK. in Tokyo I found many people only knew Japanese, and street signs/names are in Japanese. In HK our street names are english so it's easier for an American to remember say "Hennessey Road" versus some
Asian name.

I recommend Hong Kong highly, especially if you want warm weather. The city is over 70% park land and home to lots of great hiking trails that you can get to from the central business area in under 15 minutes in a cab ride that is about USD $10.

tansmets, I wouldn't recommend Jakarta for everyone, but I'd like to correct a couple of your statements. Violent crime is rare in Jakarta. For a city of its size (around 10 million)it is extraordinarily safe. It is also untrue that all expats live in compounds. Some choose to, but it is not the norm. As in many developing countries, you find a wide range of income levels, but upper and middle class Indonesians and foreigners are well integrated.

Poster hasn't shared an update in awhile, so this may miss him, but I had to ask myself why Shanghai and Beijing aren't on his list. Maybe his business isn't currently in China but for some industries it's hard to imagine an Asia-Pacific HQ being based anywhere other than the PRC.

As for me, I'd only consider HK, Singapore and Shanghai.

Yep...It's been a while since the OP has been in here, so maybe it's just a tad more daunting than the original basic plan, but...as someone has mentioned earlier, why not include Japan in on the equation..? Osaka (Kansai is a big enough airport for most folks requirements) would be a very central place to operate from, in this regard, and very easy to get in and out of.
I love Singapore, as does the rest of my small family, and we tried to live there, but the cost of living meant us losing a very healthy swag (we would have lost a min.$AUD72k a year) of our income to maintain a similar lifestyle as we currently do in OZ. Same situation in HK...Great place, but you have to fork out the bucks to get established. Mind you those involved rental accom costs/School fees and loss of income for the missus...so it's not the same situation as the OP has.
I do notice that the posting is as "Territory Manager for Asia Pacific", so as an alternative, why not even look at Australia anyway..? Darwin or (heaven forbid) Cairns area offer a very relaxed/safe lifestyle, and no problems with language barriers (mostly). From Darwin (fair enough, it's only a piddley airport) you can get to anywhere in Asia easily enough.
Just a thought, cheers,

Rick
Cairns & PNG