If you really want to control every song that is played at your wedding this is the way to go. You can hook an ipod up to any speaker system and you can create playlists for different aspects of the wedding. We got to hear all of our favorite obscure indie acts as well as the traditional dance-along favorites.
When I figured out what songs I wanted played at my wedding, I knew itunes would have them. They had the best versions and they helped me create a great playlist for the dancing and eating times of the reception. I wouldn't buy my MP3's anywhere else.
We made up two CDs from music we both liked and had purchased from iTunes. It was the best! I made one CD and Nicole made the other from music we each liked and had special meaning to us. This music was to be played in the off-time before and after the ceremony. We listened to it on the ride there and back and now we have a nice memento from the wedding as well.