30 Point Type or Larger

Filling a slide with everything you want to say does two things:

• Makes your presentation stiff: Reading from a slide defeats the purpose.
• The client reads ahead: The same way we instinctively read subtitles when they're on a movie. So, they'll read ahead, revealing the twist and ignoring your voice.

The point is to not only make the type big enough for the client to read from across the room (which they'll probably be doing), but to be selective about what you put on that slide.