Full Tracks vs. Loop Parts
I have created lyric videos with the loop and with a click track. We used it at our church and it worked great. I used some video files and full motion clips to accent the song visually as well. The loop and click was triggered by our sound guy and when it is setup in pro presenter you can start it off via midi or sound man in our case. I also used the video/loop files at a youth camp a couple weeks ago and was told that the visuals really helped some of the kids get into the worship better. For example one of the clips was a cross exploding through a brick wall in "no chains on me" the part where you shout the walls are coming down. One kid said it brought tears to his eyes because the visual made him not only hear but see what God was doing in his life. I believe video loops are a great next step in this way to present God to the lost and broken.
Example of live use I did not make this one. This is my daughter at her "Public High School Talent Show" GRIN http://www.youtube.com/watch?feature=player_embedded&v=dFMBIzeOyqs#at=46
Example of one I made for church use Here for you by Chris Tomlin