Do people with hallucinations tend to have a predominate visual hallucination?

Not usually: Auditory hallucinations are more common than visual hallucinations.

Auditory: Schizophrenics usually suffer predominantly from auditory hallucinations. Not so much visual, gustatory, tactile, or olfactory. Occasionally, however, those who do have visual hallucinations will report seeing the same one repeatedly. However, this is not always the case.

Not usually: Auditory hallucinations are much more common than visual hallucinations in psychiatric illnesses, eg. schizophrenia. Visual hallucinations are more commonly associated with with organic disease (eg. head trauma, drugs, tumors,etc.). People with acquired blindness may also have visual hallucinations. Visual hallucinations may have many forms depending upon the underlying cause (etiology).