I'm an Aussie and I'm not particularly fond of vegemite. Too salty for my taste. Marmite is VILE, more like boot-polish.
I'm surprised nobody has mentioned Promite. Similar sort of product, but smoother and sweeter. My eyesight is poor, or else I'd list the ingredients for you. It's suitable for vegetarians, however. It's the one I like on buttered bread.
The secret to eating these products is not to be generous with it. A simple thin scraping is enough on toast. A teaspoon or so of it will give colour when thickening stews etc and if you haven't browned the flour enough when making gravy, it will provide the colour you want without altering the flavour. You'd omit added salt, of course. Or, to be more accurate, I would.
Vegemite-flavoured cheese is a popular snack here with kids. Makes a good sandwich for school lunches.
I'm an Australian of Scottish, English, Irish, Spanish and Russian descent (probably a few more, as well!), and I don't give a carrot what jokes you come up with about me or my ancestors - most of whom were respectable, I'm led to believe. (Heck, we all started out as amoebae!) But if you can laugh at me, I can laugh at you, too. Laughing together is good for us all. Some people need to lighten up a bit.