babylon 5 is like TNG or DS9, the first season is pretty weak but it really picks up in season 2 and season 3 is omgwtfbbq levels of awesome. I assume you have already watched TNG? DS9 is great, and Voyager and Enterprise are ... adequate, with some great episodes dragged down by a lot of shit. Stargate SG1 and Atlantis are fun to watch, the show builds up into crazy levels of technobabble and power level ratings.
Lexx is really bizarre, but sorta galactic soap opera-ish.
Fringe is decent, started out great and kinda has leveled off but 5 seasons and the last few episodes air over the next few weeks.
Tripping the Rift was a really fucked up cartoon scifi show that parodied Star Trek/Wars.
BSG has had two prequel series, Caprica which was pretty shitty but if you watch the first 2-3 episodes and the last 3-4 its pretty good. Blood and Chrome is a webseries, haven't watched it yet.
Lost is sorta scifi, and very polarizing. Season 1 was really good though.
Clone Wars is really great if you liked Star Wars. 3-4 seasons already?
There are also a ton of great documentaries, like Through the Wormhole, The Universe, Dark Matters, Curiosity, or Nova that many times are way more fascinating than any scifi show.
