Buy a neck brace to wear during those long flights- it will support your neck a lot better than those little pillows, and help you to actually get a little sleep.

In New Zealand, most tourists visit Milford Sound- but nearby Doubtful is equally nice, and much less commercial. Tours also include a visit to one of the hydroelectric powerplants.

If you go to Australia, be sure to hit up Cairns, which has some of the best stretches of the Great Barrier Reef! There is plenty to do inland too- I cannot recommend Uncle Brian's Tour enough. It was my favorite Australian memory.