@chad3006,
Generally what happens is that after three hours someone has bought up enough of the board that the other players land on his or her property at basically every move while making little money for themselves. Eventually this bankrupts everyone but the monopolizer.
So the game usually goes in three stages of decreasing fun: the first and most fun stage where everyone is buying up property and putting up hotels; the second and less fun stage when some players start giving up their properties to stay afloat; and the third and least fun stage when it's clear who the lead player is and the game consists of rolling dice and moving pieces around the board until there's only one player standing.