My father is my only parent now... I wish that had visited my mother more before she passed away in '99 of cancer -- many a time do I regret my neglect!
Visit them while you have the chance!
My father and I do not see eye to eye on many issues, but the regret of not visiting my mother more made me push beyond ego in the attempt to reconcile with my father. It's worked, and despite our differences we now enjoy great repport. I visit Indy at least twice a year, and may be going up soon to work with him.