"Worst movies" should be films that weren't what they were supposed to be. Not merely movies that you didn't care for. For example, I hated Titantic and Gladiator, but they were well made movies that hit their marks. I just didn't care for them. So in my mind, they don't really qualify for worst movie status. On the other hand, a movie that is SUPPOSED to be socially important, campy, scary, intellectual, adventurous, biographical, etc. BUT FAILES MISERABLY to achieve these goals, qualifies.
Here is a short listing of my ideas, without further commentary.
Godfather III
Star Wars: Phantom Menace
Troy
Dumb and Dumb-er
Battlefield Earth
The Island of Dr. Moreau
I think I put too much thought into this. I gotta get back to work.
Darn you VolNation!