On reflection, maybe it's wrong of me to question and deprive P9FOS of it's 'Worst Film ever Made' status - it is a genuinely bad film but it does merit it's notoriety for another reason.
Those fun seekers tired of the Hollywood dross looking for the ultimate bad film will find great comfort when discovering the work of Ed Wood jnr (possibly the first port of call for many due to it's notoriety).
Like what has been said in a previous posts, P9FOS does have redeeming qualities, if nothing more than mere entertainment value.
It would be a shame if it lost it's position and became just another bad movie because it is far from your average bog standard B-movie.
And when entering the depths of trash films it's always good to start off with something that is at least watchable, for which P9FOS is.
Thanks for your post Thinboy regarding E2. I haven't seen that film in a long, long time and from what I recall it is indeed a terrible film, I started reading the 'thesis'

you posted and I'll have a go at tracking down this awful film myself (I presume it's in the Exorcist boxset?).
Here's a few links to The Incredibly Strange Film Show, ft a very young Jonathan Ross. This is the show that got me into bad films, there's plenty more on youtube - enjoy.
http://www.youtube.com/watch?v=iaQ1JIpe18E
http://www.youtube.com/watch?v=WxNvIpZkIcM
http://www.youtube.com/watch?v=acwCRRRIncE
http://www.youtube.com/watch?v=voEmi_onIkc