stepper: direct control but less powerfull, no feedback necessary
servo, DC, AC motors: need feedback & power modification (closed loop systems)
The most easy way is a stepper motor which has the most simple drive system without feedback.
Power
You need power for motors and steering power for ic's if used. I bought a PC power supply, because my motors need 12V and ic's need 5V. I found some good sites to modify the ATX power supply, goto: Desktop Power Supply from a PC or Tweakers.net (Dutch article). I haven't modified my power supply yet, I'm using my running PC right now...
Driver Circuits
There are few custom stepper motor drivers chips, with varying degrees of complexity and costs. It's even possible to control each coil separately from the parallel port. The industrial drivers are expensive but are also more sequire.
I will try to make my own control chip which will work with atleast with step & direction input.
