While not the best dressed presentation, Barry Schwartz's presentation on choice is worth watching for anyone designing an offering or performing consultations.

 
Via Presentation Zen:

Happiness, decisions, & the paradox of unlimited choices

 If some choice is better than no choice, and more choice is even better than that, then how can still even more choice — a seemingly unlimited array of choices in fact — not be a kind of decision-making nirvana where people make both better decisions and are happier about those decisions? Do not more choices and a greater number of options lead to better decisions? And if so, why then are people unhappy with their decisions even when a decision is a good one? Why do people feel regret even when they choose well?...

Learning to love constraints
 At the end of the book Schwartz ends with 11 ways we can end the crippling effect of too much choice or  “the tyranny of small decisions.” The last one in the list is simply this: “Learn to love constraints.” I recommend the book, but you can save your money and get a pretty good feel for the book’s content by watching this 2005 presentation by Barry Schwartz at TED (below). This is a good presentation, though you will surely have some tips to offer him on both slide design and on the issue of making appropriate fashion choices on the day of your presentation.

“Imagine finding yourself lost on the open road. You finally see a lone gas station up ahead, you’re hungry to discover the route back to the freeway. You ask the attendant for directions, and he begins to offer plan A and plan B and plan C, each with varying degrees of specific detail. Rather than finding the clear, simple, and concise directions you were seeking, your brain is now swimming in a sea of even greater confusion. Clear, simple, and concise directions are all that you want.”

We've all had a similar feeling while using a poorly-designed website, application, or even a cell phone that did everything under the sun except make calls that didn't drop halfway through a conversation.

Simple, clear, concise
As daily life becomes even more complex, and the options and choices continue to mount, making designs which are clear, simple, and concise becomes all the more important. Clarity and simplicity — often this is all people want or need, yet it’s increasingly rare (and all the more appreciated when it’s discovered). You want to surprise people? You want to exceed their expectations? Then consider making it beautiful, simple, clear…and great. The “greatness” may just be found in what was left out, not in what was left in.