I've just come across this thread and as someone said earlier to do a list of worst films ever is a bit daft as you can only have 1 worst film EVER with maybe a lot of stinkers just underneath
Also a fair few of the movies mentioned (They Live for example) are low budget crap fests anyway so arent meant to be "good" in the sense that million pound blockbusters are, films like that I just take at face value.
As for my worst film ever, well to just pick one is a very hard choice but I would probably go for -
The Italian Job (2003). I hadnt seen the original (sad I know) so didnt have anything to compare it with but I found it such a dull and boring movie. It was predictable and far fetched and I personally thought the acting stunk. No wonder Edward Norton didnt want to be there and just did it out of obligation!
As for the stinkers underneath I would go for
Titanic (Too much love story not enough disaster)
Daredevil (Over hyped and no real story)
Reign of Fire (Great effects but corny script)
Hulk (Had potential but didnt deliver - for me anyway)
Ali G (Even as a tounge in cheek piece of rubbish it was still sh*t)
The Guru (A not much happens kind of film)