Look for a lock set with two different finishes--one for the outside and one for the inside.

The one thing I will warn you about is that the newer locksets might not fit your door and jamb properly. We put in a new doorknob and deadbolt [separate units] and there was an issue with it so my husband had to order a router bit and cut the door frame so it would fit. Wish I could tell you more about what the issues was.... Our house is 46 years old.

Hayleydaniels is right; you can usually get door handlesets with the interior trim in a different finish. That way, you can match the finish of the door hardware in the rest of the house.