The type of motor driver you need depends on the type of motor you have. Depending the motor technology, they use different motor control loop.
Stepper motor driver: lots of choices for all the stepper motors.
Most RepRaps use stepper motors.
DC motors are rarely used for RepRap purposes, but There are a few projects. Also thinkable:
- brushless DC motors
- servo motor drivers
The different possibilities are exposed in the motor FAQ.
Other kinds of motors and the specific electronics required to drive each kind are listed at Open Circuits: motor driver.