I think all denominations would generally agree that worshiping any type of idol as being idolatry. Which is the obvious, statues and objects which people bow before. However many denominations also consider certain material items and actions as a form of idolatry. Things that fuel self-centeredness, greed, gluttony, a love for possessions and ultimately rebellion against God. 


Sources:
http://www.gotquestions.org/idolatry-definition.html

What the bible says about idolatry: [more here][1]

    Exodus 20:3
    You shall have no other gods before me.

    Deuteronomy 5:7
    You shall have no other gods before me. 

    Exodus 23:13
    Pay attention to all that I have said to you, and make no mention of the names of other gods, nor let it be heard on your lips.

    Luke 16:13
    No servant can serve two masters, for either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve God and money.

    Leviticus 19:4
    Do not turn to idols or make for yourselves any gods of cast metal: I am the Lord your God.

    Colossians 3:5 
    Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.


  [1]: http://www.openbible.info/topics/idol_worship