The only time to use visual aids is when you have something visual that will increase the odds of your audience understanding and remembering your message.
If you want to give a pretty good presentation, please keep the following principles about various visual aids in mind:
Video. Don't bother! This has the potential to add lots of headaches. I use video every day because I am a professional speaker; I have to show video of people speaking, and they pay me lots of money to do so. But I'm assuming that you aren't a professional speaker so I recommend that you stay as far away from video as possible. There are a million things that can go wrong, and dealing with them can become a black hole that sucks up your time. Stay away—you won't be sorry!
PowerPoint. Don't use PowerPoint just because everyone else is; but do use it if you feel you have some visuals (i.e., graphics, photos, charts, or images) that will help your audience understand your ideas better. Never use PowerPoint to simply display bullet points with words on it.
Emails/memos/handouts. If you've got a lot of text on the subject you are presenting, give it to your audience in every way possible. Email them everything you've written. Give a handout after your presentation. But don't feel the need to read to people a text memo that you have cut and pasted into a PowerPoint.
Flip charts/whiteboards. These are great for drawing something that can be more ...