American Army
James M. Gavin I know that surprises everybody here He literally wrote the book on Airborne Warfare....the first FM was done by him and he believed the division to be nothing but an extension of the calvary division, but due to the technical limitations at the time it had to become an Airborne Infantry division. Today the term Air-Mech Division is much closer to what he had in mind. RTK you feeling me man

USMC
Chesty Puller
Tough and had tremendous common sense.

British Army
J.C. Fuller my definition of a thinking general. He wrote a great book about Generalship it's disease and it's cure. Can not remember the exact title.

German army
Erwin Rommel A professional and a leader of the highest order.