Nah, I've had bread that was more amazing than the filler on a few occasions. Cheese bread is one of them. I mean, oh man, I could just eat a loaf of it. x_x Cheese topped buns are nice too, on their own, but bread with veins of cheese running through it, direct from a hot-bread shop (aka bakery in NZ) is just incredible.
As for filler, my standard fillers are any of the following...
1. Vegemite & Cheese
2. Crunchy peanut butter
3. Ham and cheese
4. Ham, cheese, cucumber and lettuce.