Before I nitpick, my good, bad, ugly:
Heat is just an utter, utter classic. Michael Mann, Robert De Niro, Al Pacino, Val Kilmer, et al at their best.
Always isn't a bad film, per se, but coming from Spielberg it got shredded by the critics (Roger Ebert basically called it as bad as 1941).
Birdemic is just so unbelievably bad that the only way to watch it and remain sane is to watch the Rifftrax version.
@jonobacon mention's Kevin Smith's story about Superman and Wild Wild West: it was producer Jon Peters who wanted a giant spider at the end of Superman Lives, the film was never made, and he went on to produce Wild Wild West. Normally, I'd have been like "yeah, Jono's just being a bit forgetful here and not remembering the details", but after the "Star Trek is the Dungeons and Dragons of science-fiction" comment, and ripping into Memento because you didn't understand it, you, sir, can go fuck yourself about movies.
Actually, in all seriousness, Jono, please don't introduce Transformers to Jack using the shit Bay movies; go for the animated movie and the cartoons! They're way more fun and nowhere near as mean-spirited (especially as you move into the really shit sequels).
And @sil is thinking of Speed 2, not Under Siege 2 (which was Under Siege on a train), but his selection of one of my favourites Sneakers saves him from a slapping. Well, almost, until I heard the Blade Runner comment. HOW CAN YOU HATE BLADE RUNNER?! How can a movie that starts like this be anything but FUCKING GREAT?!