I'm a big fan of our Maori words - some are just so delightful to get out.
Aotearoa - the Maori word for the land known as New Zealand, translates to "The Land of the Long White Cloud". I'd be happy if we changed our country name to that, if only so we aren't so far down the line in the Olympic procession.
Turangawaewae - a place where you feel connected
Te Toiroa Tahuriorangi - not a word but the name of a rugby player in New Zealand. Just absolutely fantastic to say and also to hear the commentators wrap their heads around it.
Also, Refugee's suggestion, Ameliorate is one of my faves. Cathartic. Incandescent.
Edit: I thought of another - Whakatane. A town in the North Island - phonetically it's "Fuck-ah-tah-ney".