Like any other object, except the cross has a more sincere and heartfelt representation for believers because of the work Christ did on the cross, it isn't that we have one in our home, around our neck, key chain, or some such.
Our God is what we worship and adore. As long as we are worshiping the Lord God, the Great I Am, everything else is ok in my opinion to have. A cross, a picture of Christ, a picture of the wife and kids, whatever.
What we worship is the key to is it acceptable to God.
(my thoughts)