If you want to see how the East and West blend then by all means go to the Philippines. You can see lots of exotic places especially the beaches, the food is good and the people are nice. I'm sure you will want to stay in that country.
ShriLanka is beautiful, with rain forests, jungle and mountains. You can visit wild elephants one day and wake up the next morning on a tea plantation. A vist to the Temple of the Tooth in Kandy is a must for all visitors but for me, it was the people and the wild life that made my visit so special.
It really does depend on what you want out of Asia. I have spent time in all countries there. In every country North is different to South, beach differs from mountain and town from city...and then various towns and cities offer varying delights. I find if you give anywhere 24 hours, really sink into a location, accept all and try new things every day you will have a memorable time. The Philippines are great but so is Thailand. The food is very different in each place but equally delicious. Hong Kong! Amazing, especially at night. There are cheap flights there from the Philippines and cheap flights from Thailand to the Philippines. And yes Dohn is right Laos and Luang Prabang are great as is the river trip there from Thailand. Got a month? You can see all for not too much cash. Then again you could spend the whole time lying by a hotel pool having a wonderful time and see nothing. It is all about choices.
Sab Oh - Okay maybe not all just Thailand, Laos, Vietnam, Cambodia, The Philippines, Singapore, Malaysia, Indonesia, Sabah, Hong Kong, Macao and China. Some of these several times for varying lengths of time and travelled about in each. Never been to Japan. Always fancied it. Maybe one day.
I have lived in South Korea and China, and of course seen Hong Kong, and Singapore and love them all. It would be pretty hard to pick just one destination, so I suggest do a tour of as many places as you can afford time and money wise. You will find extra ordinary things in all Asian countries and like me yo may find it difficult to choose one country as best.
Of course as you can see I've got a lot more places to visit. I currently teach English in China. I love living in a country to really get to understand the culture better.
Like what everyone said, Asia is pretty big and diverse, so it would be hard to just pick one. Thailand has the best food, friendly people and the most amazing beaches (I was born and raised there, so I might be biased). Japan has very beautiful countrysides - the Mt. Fuji/hakone area is breathtaking. My personal favorite is Nepal. I was there for 2 weeks with 1 week spent trekking in the Annapurna mountains - it was THE most amazing experience! I absolutely love the durbar squares in Kathmandu, Patan and Baktapur -- some really exquisite architecture!
i have my own views on places in Thailand but iam more interested in finding out about you and why you would choose your favourite place have you lived there our do you expect to on retirement our do you just need a...