> > if you asked a random citizen of Canada, Australia, New Zealand or the UK to name a single supreme court judge they'd probably be unable to
> Don't each of these countries feature sovereign Parliaments [1]?
Australia does not have a sovereign Parliament. The Parliament of Australia is subject to the Constitution of Australia, and the High Court of Australia can and sometimes even does invalidate Acts of the Australian Parliament as violating that constitution. So in that regard, the Parliament of Australia has limited powers just like the US Congress does. The big difference is that while the US has three coequal branches, Australia only has two – the legislative and the judicial branches. In Australia, while the executive branch is theoretically equal to the legislative branch, in practice the executive is subordinated to the legislature.
Actually the question of whether even the UK Parliament is sovereign is debated. Keep in mind the UK has three legal systems: (1) England and Wales, (2) Scotland, (3) Northern Ireland. Northern Irish law is based on English law, so Northern Irish constitutional law has at best minor differences from English constitutional law. By contrast, Scottish law is a completely distinct legal system, with a very different heritage (based on Continental legal system, ultimately tracing its origin to the laws of the Roman Empire), and that includes a distinct body of constitutional law. And while it is true that parliamentary sovereignty is a fundamental principle of English constitutional law, its status under Scottish constitutional law is debated. In the 1953 case MacCormick v Lord Advocate, the Lord President Lord Cooper (the most senior judge in all of Scotland) said that "the principle of the unlimited sovereignty of Parliament is a distinctively English principle which has no counterpart in Scottish Constitutional Law", and left open the possibility that if the Parliament of the UK passed an Act which was a clear violation of the 1706 Treaty of Union which created the United Kingdom – for example, if the Parliament of the UK tried to abolish the independent Scottish legal system and impose English law on Scotland – the Scottish Courts would have the power to invalidate that Act. In practice this question is unlikely to ever arise, because it is politically inconceivable that the Parliament of the UK would ever actually pass such a law. (The case was about whether Queen Elizabeth II was allowed to use the regnal number II in Scotland, despite the fact that Scotland had never had a Queen Elizabeth I – the court ruled that the Treaty of Union said nothing on the topic, so the Queen's choice of what regnal number she used could not be said to violate the Treaty.)
To answer the original question, I definitely remember the name of one former Australian High Court Justice – Michael Kirby (who is famous for being the first openly gay High Court justice). I am a bit of a law nerd, but I don't think you need to be a law nerd to remember that.