Nailing colours to mast time.
Asimov, Heinlein, Silverberg, Clarke, Dick, Niven, Pournelle - you get the idea? Liking Peter F Hamilton these days - bit overblown at times, but in the spirit of the old masters.
2001/Solaris - Solaris (original & remake) is one of those films designed to make you think "What the F*** happened there?", 2001 tries to do the same, but is a bit more transparent. Both are good in their own ways - some days I like cheese, some days I like chilli, knoworramean?
Dr Who, Torchwood et al should not really be classified as Sci-fi - they're action adventures with a 'different' science theme at the core, same as Star Trek. If the Beeb were to produce proper science fiction .... I'll leave that as an exercise for the class. Imagine trying to do the Foundation saga or Heinlein's "Future History" (Lazarus Long, anyone?) on a BBC budget .... *shudder*.