At the top of the list is Jay and Silent Bob Strike Back. Watching this movie is like hunting for Easter Eggs in the manure pile. When you finish, you feel dirty, and you and I both know you're not going to enjoy those eggs very much.
Let me explain: the movie is a series of gags that we've seen before. They're funny enough, but they don't justify the bracketing material which curses bluely enough to embarrass pretty much anyone short of Kevin Smith, who directed the film. There's no reason why this piece of work could not have been presented in a PG-13 format, and still lampoon everything it needs to lampoon. Sure, you can argue that the movie is, in fact, parodying works that overuse the f-word, but that point could have been just as easily made with bleeped profanity (personal note to Kevin Smith: that would have been funnier.)
The best part of the whole mess is the light-saber fight at the end. Unfortunately, if you rent the DVD just to see that, you're still rewarding Kevin Smith for defecating in the film can, and I would hope that you feel as morally opposed to that as I do. (Sadly, my money has already been spent there... I apologize to God, America, and Hollywood for casting my fiscal vote as I did).
Next on my list of "Don't Bother" is Supercop 2, starring martial arts sensation Michelle Yeoh. After seeing her in Crouching Tiger Hidden Dragon, Supercop (in which she played alongside Jackie Chan), and Tomorrow Never Dies, I figured I was in for at least a little bit of a treat. She's a great athlete, a solid actress, and can be a commanding screen presence. Unfortunately, the script for Supercop 2 appears to have been written by a laboratory bonobo whose bottled brains were replaced with a bowl of three-day old ramen noodles, and the fight scenes were edited by Edward Scissorhands' stoner brother, Bubba Sharpknees. The only way for this movie to suck any harder than it already does would be for it to be placed in a hyperbaric chamber where the air pressure is increased.
Finally, for those of you thinking about renting something for the baby to get smarter by, stay well away from Baby Bach or Baby Mozart. Both videos were produced on the premise that if HEARING classical music stimulates babies to be more verbal and more intelligent, then WATCHING classical music should be even better. The argument falls to pieces, however, when what you are watching is glorified sock-puppets, and the rich timbres of orchestral music have been replaced with the 'ping, dink, dink, bong' of an 8-bit synthesizer. If you want your baby to be smarter, and you want to employ music to this end, put on a classical CD (or any intellectually engaging music, for that matter) and PLAY WITH THE CHILD. Dance. Throw a ball. Sing. Interact. And remember, there is no way that plopping a baby in front of a television is going to make them more likely to intelligently interact with the world around them.
Oddly, the same holds true for adults. But you already knew that, because you are here instead of in front of the television. Bless you.