heathtech and stevez have summarized this very well, especially regarding the point of fusing close to the battery to leave as little unprotected wire as possible.
Many vehicle circuits are "lowside" switched, meaning the ground side is switched on and off. This has two desired results. One, this simplifies any electronics in the circuit, since switching is referenced to ground, and two, since the switch side of the wiring is often the longer run of wiring, exposed to more hazards, the worst that can happen if the wire shorts to chassis is the device turns on.
In all my vehicle installations at work, the fuse is always located directly at the battery, or inverter/generator, protecting the wiring, which is really the point of the fuse anyways.