If you can...do both breh. There are plenty of nonstop flights b/w HK and Bangkok. AirAsia is the cheapest carrier I think .
Thailand
Although I flew into Bangkok, I didn't explore the city because there were protests, explosions, fighting in the main city center...so I said fukk it and just went to the island/beach region. I visited Koh Samui and Koh Tao. I've been to the Caribbean and Hawaii.....and neither of them have shyt on Thailand's beaches. The clearest, warmest ocean water I've seen. Living coral reefs with thousands of fish just below the surface...considered one of the best snorkel/scuba areas in the world(Koh Tao). You can stay for a cheap as $15/day in a private beach hut/bungalow. Meals are $3-8. Most restaurants in Samui were actually people's houses....they cook in their kitchen and have tables set up on their front porch. Legit massages(best I ever had) are $8-12/hour
Most of the other tourists are Australian or UK. Koh Samui doesn't have all the crazy, explicit bars that Thailand is famous for. I believe Phuket(the most visited island) has them though. Check out a Muy Thai fight while you're there. The people are very welcoming, most spoke English. The only drawback for me was driving around. They drive crazy as fukk....scooters fukkin everywhere. Two scooters will pass you at the same time on a two lane road....while cars are approaching in the other direction.
There were close call accidents every time we had to go somewhere...shyt was nerve-racking.
Hong Kong
If you like food, urban architecture, and opulence..you'll love Hong Kong. Tons of rich people from all over the world. Incredible networking/business opportunities (HK is pretty much the western gateway to China and its resources) Bar hopping consists of going from one 80 story rooftop to another. After visiting HK, American city skylines seem pretty
now (including NYC). The food was amazing almost everywhere I went. I was told the food is so good in HK because since there's so little space, the competition to be a good restaurant is high. Go to a dim sum restaurant and anywhere with fresh noodles. Make a reservation to check out the Ozone Bar at the Ritz (highest bar in the world). Make time to visit Macau, another provincial "country" island about an hour turboferry ride from HK. Has a bigger gambling revenue than Vegas(even has a MGM & Wynn casino). Used to be owned by Portugal.....so there are Portuguese influences throughout. Also try some Macanese food (Portuguese, African, Chinese mix). Staying on Hong Kong island can be ridiculously expensive....it's cheaper to stay in Kowloon, across the bay from HK. their metro system is A+ and runs across the bay, although it can be unbelievably crowded. At 8pm every night, the skyscrapers do a synchronized laser-light show to music. Best place to see it is from one of the dinner cruise type boats that leave from Kowloon. Also you gotta go to the top of Victoria's peak for the best view of the city(where my avatar pic was taken). Best bet is to take a taxi to the top, then ride the train back down....the train to go up has hour+ lines.