Neither Adobe Reader nor Apple Preview does a good job with PDF presentations. There is a free, open-source program called Skim which is much better. Compared to Apple Preview, it doesn't default into slideshow mode, doesn't display a grey navigation bar over your slides, and works well with most presentation remotes. Compared to Adobe Reader, it does disable the screen saver and auto-sleep during a presentation, doesn't display the stupid hand cursor, and uses Apple's superior font rendering. It also has lots of other features for reading and annotating PDFs, but I really only use it for presentations.