I just came across this article via http://www.petefreitag.com/item/110.cfm.

In a nutshell, by removing about 90% of the plugins you can increase the loading time of Adobe Acrobat Reader by at least 3X. I've just tried it and it works a dream. If you are looking for some PDF's to try this on then goto http://www.google.co.uk/search?sourceid=navclient&ie=UTF-8&oe=UTF-8&q=test+filetype%3Apdf