Covet, in a good way, means,
"eager to obtain"
(a good thing... such as wisdom,
spiritual gifts, etc.).

(1 Cor. 12:31)
"Covet", in a bad way, means,
"to want greedily;
or to desire an
unlawful thing";

(Col. 3:5) 

Mortify therefore your members
which are upon the earth;
fornication, uncleanness,
inordinate affection,
evil concupiscence,
and covetousness,
which is idolatry:

Colossians 3:5