A well-designed slide deck will aid in an audience's understanding of topic. However, the best designed slide deck cannot overcome a presenter's lack of skill.
Lea Pica's website, which contains links to her blog and podcast, and her presentation offer solid tips and a good starting point for developing and executing a presentation. For a longer discussion (plus a well designed text), Andy Goodman provides more discussion about presentations.
Seth Godin's blog post ties relationship between slide deck and presentation.
Barry Ritholtz's presentation explains how bad presentations coupled with bad slide decks kill the audience's interest.
Tim David's post gives suggestions on how to develop a better elevator pitch, which is a presentation that lasts two to four minutes.
Tim Wilson's 10-entries cover different aspects of presentation. On each entry, he provides several exemplars. This entry gives seven tips for presenting data-driven topics.