We're putting together playlists for dinner and dancing for our wedding. We've found, though, that great dinner or dancing-appropriate songs are hard to come up with on the spot. It's more likely that we'll hear something on the radio, in a store, etc. and think, "We should definitely play that!". Hence the RTM lists: one for dinner, one for dancing. With my iPhone app, it's super-easy to add songs when I hear them (and before they fly out of my wedding planning-addled head again).