I am a regular traveler from Hawaii to different countries in Asia with the majority of my trips going to Thailand. From Hawaii, there are no direct, non-stop flights to Bangkok, Thailand. I either have to go through Japan, Korea or Taiwan.
I have never booked the flight on Korean Air through Seoul because the flight times and cost are worst and the highest. I have flown through Narita Airport in Tokyo and Kansai Airport in Osaka but my preferred flight is on China Airlines via Taipei.
Prices on Japan Air and China Air are close but China usually wins out. Northwest Airlines and United also fly to Bangkok via Narita, but, I prefer to travel on Asian airlines over U.S. carriers.
The primary reason I choose China Airlines is the arrival time. All the airlines I mentioned above arrive in Bangkok right around midnight which gets me to a hotel at two or three in the morning. China Air has flights two days per week that arrive at about 4 PM and it is so much better to arrive during the day.
Lets get back to the layovers and what to do while you are waiting. For the layover I have in Taipei, there is not much time to do anything since the layover is...