I would recommend a goose over a llama. In my experience with llamas, they tend to be hit or miss as far as guard animals go and they really aren't very good at being pets. They tend to be skittish. They are also quite a bit of work in regards to monthly shots and shearing.
I've had good luck with my geese scaring away predators. They really only got loud when someone was near the chicken pen. I kept my geese in with the chickens (I had two boys) and they were quite friendly since I raised them from goslings. Also pretty cheap as far as care goes.