Not seen Twilight Zone.
I thought Black Mirror was excellent! Many of the concepts featured in the series don't seem that far fetched.
I'd have to say Stargate: Atlantis, were I asked what my favourite sci-fi series is. SG-1 takes second place, with Fringe at third and Star Trek: TNG taking fourth.
There are many other shows I've thoroughly enjoyed watching, but that'll do for now.