A good Home Theater receiver will greatly improve your movie watching enjoyment.  A great Home Theater receiver will put you right in the middle of the action.  5.1, 6.1 and now 7.1 surround sound systems can listeners on great journeys with sound coming from every direction to make you feel like you are really there.  Features like Dolby Digital, DTS, and DSP modes allow the listener to hear the movie soundtrack the exact way that the director intended.