So, when you give a presentation, do you have an introductory outline slide? Chris Rowan of highly allochthonous is pretty clearly on the anti-outline slide camp.
I have to admit that I tend to include an outline slide. I never used them before I went to grad school, but my program had endemic outline-slide use and I succumbed to peer pressure. Before I'm drawn and quartered, I should explain that my "outline" slide is indeed a very quick overview, emphasizing "why this matters" and not "intro, methods, results, lather, rinse, repeat".
Here's the thing: for a short, well organized talk, the outline slide is superfluous. Your audience should be able to follow your presentation on their own, aided by your own slide transitions. However, I've been to way too many painfully dull presentations where the speaker appears to be mired in details and never bothers to explain why their topic is interesting/important/whatever. Those talks would be a lot easier to take if the audience had some idea where the talk was going.