A great site about professional presentation design is Garr Reynold’s blog Presentation Zen. He has a beautiful style, an Asian touch, which is elegant and powerful.
I subscribe to the blog and will refer to several of Garr’s blog posts in my Presentation category.
I have bought his book ‘Presentation Zen’ and will post a review on it once I have finished it.
My review is here: Presentation Zen is a great book.