I didn't mention it before, but towards the end of my first trip to the National Zoo I visited the Asia Trail to have a look at the giant pandas, red pandas, and Japanese giant salamanders. On my second trip, I happened to enter the zoo close to the other end of the trail, the end I hadn't seen.
A sloth bear, a strange-looking bear specialized for feeding on termites (though they are omnivorous and will eat many other things as well).
Some fishing cats. As implied by their name, they are skilled at fishing and swimming. Their enclosure had a pool stocked with small fish, though it's not visible in this photo.
A clouded leopard, one of the most arboreal of all cats.
An Asian small-clawed otter.
I also returned to the Japanese giant salamander exhibit to try and get some (good) photos of it, but failed in that endeavor, and I didn't see the red pandas this time. As for the giant pandas, giant pandas are quite interesting evolutionarily and do their part as mascots of worldwide conservation efforts, but they get enough attention and frankly aren't that enjoyable to look at in zoos compared to certain other animals in my opinion.
Also, am I seeing things or have the total votes on the sidebar poll been decreasing? Only a couple months to go guys, don't skew the results now!