Most Scifi fans I have ran into can pretty quickly rank the four stars –BattleSTAR Galactica, STAR Trek, STARgate, and STAR wars, but what lesser-known or less-prestigious shows hold a special place in your heart?
As for movies, Primer (2004) is one of my favorite. The first movie of its director (Shane Carruth), filmed with a ridiculously low budget of $20 000. It's hard science applied to time travel.
Be warned that this movie requires at least 2 or 3 viewings to really understand its story. Yes, it's that complex.