Cambodian food is absolutely my favorite Asian food. I didn't eat a huge variety, but I really liked everything I ate. One day at lunch, I got to sample a bunch of different things. Khmer Amok was definitely my favorite. It looks like a curry, and has some similar qualities, but has a much more robust flavor. It's less of a "pow" and more of and "oooo."
I also tried catfish, frog, spring rolls, a few different kinds of salads, and some pastries. Admittedly, I didn't eat as huge a variety as I had hoped, but I really liked the amok so I had that for more than a few meals.
Vietnamese food was really good, too. It was a lot of noodles and vegetables. It was a bit spicier than Cambodian food, and also a little more fried.
We had really great food on the Halong Bay cruise. It was nice to have a lot of different foods presented to us. I don't think I would have been able to take in such a variety if we hadn't done an organized tour. I don't really have a memory of eating crab prior to being in Asia, and I think the only time I've had it in Korea is when it was part of a soup. I could not get enough of it on the tour. It was a little more buttery than I could usually handle, but the whole thing was so awesome.
In Thailand, we ate a lot of foreign (western) food and encountered another application of crab. It was seriously fantastic. The restaurant we visited was a "pick-your-own" style, and we ordered 2 crabs and like 15 giant shrimp. Since there were only 3 crab left, the lady just gave us the last one for free! It was definitely one of my favorite meals of the trip.
Overall, it was a really delicious trip!