Similar to Death By Powerpoint, this billboard above is a great example of what NOT to do when it comes to designing information that is intended for quick impact. The key message, which I thought was very well phrased, was lost amidst the jumble of text at the top and the bottom:
You have no more right to pollute with tobacco smoke the atmosphere which clean people have to breathe, than you have to spit in the water which they have to drink.
Here’s a great Slideshare presentation on how best to avoid Death by Powerpoint:
I would also highly recommend the work of Presentation Zen as a great place to learn better design for communications.