My favourite station Down Under is Melbourne's Southern Cross (formerly Spencer Street).
Many might disagree on this choice - the station was redeveloped wholesale along with the adjacent Docklands (for which the station is a gateway) and re-named in the early 2000s, and there's no "old railway" or heritage feel about the place. Southern Cross now looks more like a signature airport terminal with an enormous (and hugely expensive) swooping curved roof.
But the two things I do like about it are:-
1) It's light and airy, with its Number 1 purpose clearly being a big city railway terminal - not some huge shopping mall, or office development with a few cramped, gloomy platforms hidden away somewhere underneath, as can happen with some redevelopments (looking at you, Manchester Victoria)
There are convenience stores, cafes and bars on the concourses, but no more you'd need for a "proper" railway station.
2) With modern railways around the world becoming more homogeneous, bland and "efficient", there's still quite a variety of railway operations to be seen at Southern Cross.
On one side there are through platforms with a continuous procession of EMUs running around the Melbourne city loop to suburban destinations (S-Bahn style).
Then there are terminal platforms with various regional / commuter DMUs to nearby cities like Geelong & Ballarat, and loco-hauled "inter-city" trains to more distant places in Victoria. At peak hours, these arrivals & departures are pretty frequent and can be easily observed from a pedestrian footbridge (without needing to swipe your Myki card).
At the eastern side of the station are platforms for interstate trains to Sydney and Adelaide. These last two, plus a few of the regional Victorian trains run on standard gauge, whereas most of the rest of the tracks are 1600mm broad gauge. So quite a bit of variety and interest there.
Southern Cross Station by Bidgee, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons