A simple symbol that tells about nature and the US coupled with a simple, easily readible font. I've checked and the white version works great on photographs.
We like the buffalo best but it needs a little more of something to exaggerate it a little to feel more unique and bold. I am not sure if that makes sense.
I liked the look of #605 on photos, but I understand it may be too abstract. I've treated the buffalo with an effect which makes the image look more lively. Hope you like it.