Most people would feel naked and stripped if they were not accompanied by a visual aid of some kind.
The truth is that there are times when visual aids are not necessary and other times when the equipment fails and you will have to move to plan B without it. If you have put enough thought, preparation, and strategy into it before then you should not have to rely on or freak out without visual aid.
Visual aids are supposed to be a support to your presentation not the featured star. If you have prepared for your presentation thoroughly and truly know your information inside and out then you will be able to have a meaningful speaking engagement even without the use of supplementary aids.