For Thai food, I have 2 favorites that are not only functional, but wonderful reads on the culture/cuisine. They are also gorgeous enough to put out on your coffee table for guests to peruse.
The first is Thailand - The Beautiful Cookbook. This was originally put out in hardcover for around $50, & was reprinted in hardcover for considerably less a few years ago, if you can find it. It has, however, also been put out - by Border books, I believe - in a softcover edition.
The second is Southeast Asia - another hardcover beauty that's worth searching out. The photography, readability, & easy-to-follow recipes make for a lovely experience.
For Chinese cooking, one of my hands-down favorites is an unillustrated (except for some black-&-white drawings) volume - The Key To Chinese Cooking, by Irene Kuo. If you only have one Chinese cookbook, this should be the one. It may be out-of-print now, but is worth searching out in 2nd-hand bookstores. I'm sure a copy can be found at one of the online 2nd-hand dealers. Per The Washington Post "A splendid, superbly executed volume that teaches as it tempts the reader." I've yet to make any dish from this book that didn't turn out fantastic.
(Edited to add that if there was only one technique that made this book worth the few dollars I paid for it, it was "velveting" food before stirfrying it. While I've been stirfrying poultry & seafood for YEARS, the difference in the resulting dish was AMAZING. My husband & I looked at each other after the 1st bite of "pre-velveted" stirfried chicken with "why didn't we know about this before" expressions.)