Whatever media aids you use to help present a professional presentation or lecture, success of the entire thing depends on preparation, knowledge and a lesson plan. Have a backup too (you never know when the equipment may let you down). Remember that Prior Planning and Preparation Prevents P**s Poor Performance (the 7 P's).
Personally I find that the whiteboard works fine in conjunction with an OHP, although the trend at our club does tend to be moving towards computer based presentations.
Kermie
[ 17 December 2001: Message edited by: Kermit 180 ]