When you are standing in front of the audience delivering your best man speech the authenticity in your communicaiton will carry a great deal of whether or not you are successful in maintaining the audiences attention.  For this reason, the ability to speak your speech while keeping eye contact with your audience is critical.  Using note cards or an 8 by 11 sheet of paper will greatly diminish the spontanious charisma that you otherwise could have had.  The solution to this is the following memorization technique for your speech.