"Amateurs talk about tactics, but professionals study logistics." - Gen. Robert H. Barrow, USMC
Weaponsman linked to an interesting article about the British logistical problems during the American Revolution. It had never occurred to me before, but seemed obvious in hindsight that supplying an army across the Atlantic in the eighteenth century would have been... challenging. What's more surprising is not the difficulty of the endeavor, but how good a job the British ended up doing.
Any boy howdy am I glad I wasn't born back then:
Forget massed deployment of Ferguson rifles, or uzis from the future or any other alt-history wank. If you wanted to go back in time and make the British empire unstoppable in the late eighteenth century, slip them the secrets of modern preservatives.
Or germ theory.