Is there a fundamental reason there are two distinct types of energy? There are many forms of energy commonly encountered in physics: chemical, thermal, sound, electromagnetic, nuclear, gravitational, etc. But if you drill down, they are all either:


*

*Energy of motion - Kinetic Energy

*Energy of position - Potential Energy,


just at different scales. Is there a more "fundamental" reason why energy has this bimodal nature?
 A: Rob's answer is fine, but there are other perspectives.
First, note that potential energy is an abstract concept that doesn't cut it in general: Energy (or rather stress-energy-momentum) is the source of gravity, so we need to know exactly where it is located. In case of a system of electric charges, it's contained in the electromagnetic field. The difference in potential energy between two distinct arrangements of charges is the difference of the energy densities of the electromagnetic fields, integrated over all of space.
Kinetic energy then comes in because energy is not a scalar quantity, but the projection of energy-momentum onto the time axis of an observer. In some cases, it's possible to assign a rest frame to particular blobs of energy. We call energy measured from that frame 'mass'.
This description isn't entirely complete, as gravitational energy is a more subtle issue I'm happy to skip over in this particular answer.
A: You are partitioning energies into 


*

*energies associated with motion

*energies which are independent of motion


In a system governed by linear second-order differential equations like $m\ddot{\mathbf x} = \mathbf F(\mathbf x, \mathbf v) $, your system is entirely specified by positions and velocities. If you have energy remaining when the velocity vanishes, position is the only dynamical variable remaining.
Except mass --- which has its own associated energy, the intrinsic energy $mc^2$.
