I always "overbook" on books for long trips. I'm still carrying a couple of "emergency" paperbacks, but with eReader and now the Kindle Reader on my iPod Touch, I can carry zillions of pages of reading matter with only a few electrons worth of weight penalty. I just need the time and the battery life to read them.
I bought a couple of Kindle books including a book of essays on China by James Fallows, a favorite writer (Postcards from Tomorrow Square) - this meets my geographically related requirement. But mostly I sought out free books to fill my Kindle home page, and there were a few interesting ones even outside the public domain classics category . I usually don't do "fantasy" but one of the free current books was His Majesty's Dragon. It had great reviews so I downloaded it. It's sort of "alternate history fantasy" in a world where (talking) dragons exist and have been pressed into service to carry pilots and provide air support during the Napoleonic Wars! Sounds crazy, but I started reading it, and I think I'm hooked. I keep going back to it so I think this will be my first book for this trip, jumping the stack as usually happens. Serendipity rocks.
Update: I read His Majesty's Dragon on the long flight from Chicago to Hong Kong. Great book! Who cares about genre? This is just a great story with great characters, some of whom happen to be talking dragons. I read somewhere that Peter Jackson ("Lord of the Rings") bought the movie rights to this series - I hope it makes it to the screen. Meanwhile there are at least two sequels that I'll probably buy and read sometime (but not on this trip - too many others in the queue) . The free first book thing is good marketing.