Switzerland
Although Switzerland is not a member of the EU and it is a bit smaller than New Zealand, Swiss passport holders and citizenship has a lot of impalpable bonuses that push it above Singapore and New Zealand. Swiss passport holders can visit 169 countries visa-free or with visa upon arrival. Switzerland is also a member of Schengen zone so it only means that Swiss citizens can freely live anywhere in Europe. For traveling inside almost all of Europe, Swiss citizens can use an identity card.
