Ted, it will depend on the real purpose of your trip, and on what will you do while there.
To me, without a doubt, Thailand is a MUST to visit.  It is a place with beautiful sights, a lot of historical and cultural places, many temples and statues to their Gods on one hand, and on the other all the sex you may want.  Of course, the capital have had some political unrest, but if you stay away from that area, you are safe.  I have been there many times, took normal precautions, and each time had a blast.

Also, but not as developed as Thailand, I would suggest to you Vietnam and in third place Cambodia.  You will need again to be a bit more cautios than in Thailand, but to me it was worth the trip.  The highest risk you normally will face is pickpockets or purse snatchers.  No kidnapping of tourists is going on now.  And if you get one or two other Ex-Pats to go will you, even better.

You could try Malaysia, KL is very nice city, also Penang and Lankawi are nice. The whole country is a weird but pretty cool mix of indian and chinese culture. I like the food there.

Every Asian country has its interest points.  For me, as HappyExPat said, is Thailand.  I absolutely love that place.  Pattaya is the happy place my mind goes to when I am having a bad day.  :)

Also, Vietnam, Cambodia, Laos and Phillipines are also great for a visit.  Maccau is also a great place to go if you want something really close by.

I absolutely love SE Asia, all its different countries have something different to offer, but friendliness, good food and hospitality is universal to the region.

If you're after beaches, relaxation and hedonism then Thailand cannot be beaten. While famously friendly, a lot of the people in tourist areas are understandably jaded with stupid westerners. For an intense, immersive and mind blowing experience then Cambodia or Vietnam are wonderful, Malaysia is a great cultural mix and more advanced than than the others and Bali has a nice vibe.

For me, if you can accept that a holiday doesn't have to include a beach, then Luang Prabang in Laos, and the surrounding areas, is a little paradise. Clean(er), quiet, historically interesting, good bars, a nice French influence on the food, with the most gorgeous surrounding countryside. Plus it's pretty safe as long as you don't go blundering around the jungle, and dead cheap. Thank goodness that Laos is so far complelely overlooked by package tourists.

I would say NEPAL...coz the nature there mountain,lakes,river.....n yes not to forget the great everest stands right there....So a must go place.