Right, yeah tanks are probably my favourite area man. They had their heyday in WWII, but in the modern era wars are generally no longer fought between two professional armies: it's generally a professional army vs. lose networks of guerilla fighters. Tanks are fairly useless in this scenario, you're better off using special forces for the actual fighting, the regular army equipped with mobile armoured vehicles for occupation and sending your main attack against the support networks that keep the guerilla's funded and active. Tanks are only really good in the state vs. state situation where it's masses of troops going up against each other and even then, Air superiority is still the main way to victory.
Australia is and should be primarily concerned with having a decent navy with a decent air strike force, much like Britain, because it's basically one large island (technically a continent). Germany on the other hand had completely different geography to deal with: it became good at mobile ground warfare and tactical air support in WWII because it has relatively little coast line and enemies on all its borders. The treaty of Versailles restricted the size of it's army so they concentrated on building their army and infrastructure so that it had the mobility to fight and beat Russia in the east and then France in the West if it ever had to: that's why tanks became a central part of the German army during WWII and why they make some of the best tanks during the Cold War. It was thought that Germany would be the centre of a massive battle between NATO and the USSR if the cold war was to ever erupt into a ground battle.
I'm guessing you watched the "Greatest tank battles" show or whatever it was? I've seen a few episodes of that, a good one is a tank battle between Israel vs. Syria in either the 6 day war or the Yom Kippur war (can't remember which one) where the Israelis took out huge amounts of Syrian tanks with relatively few of their own. Interesting stuff! And of course the classic tank battle was Kursk where the Russian t-34 started to show it's worth on the battlefield. That was a nice tank.
