How do you think of different root systems?

When "planning" a root system, how do you think of different root styles?

I'm thinking:
surface roots - hold the surface dirt from breaking apart
deep roots - staple the dirt into place to prevent massive landslides

A book that helped me better understand the variations/types of plant roots is Roots Demystified by Robert Kourik. There is a more recent book written by Robert Kourik titled Understanding Roots that is aid to have even more information compared to the older book but I have yet to read it.

I still am learning how to best incorporate particular root systems into my landscape planning so I can't provide advice but I'm right there with you trying to learn as much as I can!