LOVE vegemite. I crave it when I havent had it for a long time. I love it on butterd toast. I have sandwhiches of it with lettuce and cheese. Its great if you get a sheet of filo pastry, spread a thin layer of vegemite, a sprinkle of grated cheese, roll it up, cut it so it forms disks and shove it into the oven. mmmmm. My brothers have it with Jam, usually blackcurrent or even marmalade - which I've never understood.
If you're a vegemite fan have the lettuce in your vegemite sandwhich. Hell if you're not a vegemite fan try it, just have more or less a cheese and lettuce sandwhich with a VERY thin layer of vegemite on on epeice of bread.