The New 'Dredd' movie was a blast. Lots of nods to fans ('Chopper' graffiti, for example), and pretty true to the comic. Although those of a sensitive nature should be made aware that its very
very violent and bloody, and the overall plot seems to be lifted from 'The Raid', a Indonesian martial arts film. Not that either of those factors is a bad thing !
I'll also agree that 'Dark City' is a cracker of a film, and slipped under a lot of people's radars. If you haven't seen it, it's definitely worth your time.
John Carpenter's 'The Thing' rates as one of my all-time favourites. A lovely cold slice of paranoia and shapeshifting madness.
And if Donny Darko can qualify for this thread, I'm sure 'Pi' by Darren Aronofsky can too. Not everyone's cup of tea to be sure - but it does have a cracking soundtrack !
As for worst film - having run a university scifi/fantasy film club in the past (with very limited resources), a lot of our 'B' films were very....ermm... 'unique' ? 'Special' ? Time has mercifully erased most of the horrors, thanks to psychological counselling.
I don't think I could honestly tell you which bit of 80's dreck was worst. Maybe 'The Ice Pirates', as we're limiting this to science fiction ?
Although when it comes to memorable/unforgettable, Roddy Piper in 'Hell comes to Frogtown' is burnt into my mind and will probably never go away. Explosive codpiece. 'Dance of the Three Snakes'. Egad.