The plaintive version. I have no idea as to the authenticity of the performance, but it sounds gorgeous.
The military version I can see how one could march to it, but I think it might be offputting for anything else.
And last but not least, the children's cartoon version, which explains all the words. I'm really not sure what the cowboy is doing in there.
Speaking of cowboys and bafflement, there is always the crossed-with-Sims version of Coward of the County.