I'm a big fan of stargate. It's a great series with a lot of back story fictional languages and fictional cultures. But the reason why I really like it is that it's set in modern times (starts late 90s) and still is a science fiction show. They also tie in conspiracy theories and ancient alien stuff which is really neat. It's fairly unique I think for a science fiction series. it's also totally true
I didn't watch enough DS9 or Enterprise to really judge them, but I was OK with Voyager; tons of action schlock, but the morality episodes that I love from Star Trek were legit, at least. I do agree TNG is the best, though.
Since you're so familiar with the series, I'd recommend fiveminute.net to get some short humorous synopsis of your favorite episodes. It's very good and are all quick reads. Some favorites -
Blurb for TNG season 4 episode "First Contact: When the Malcorians get upset at having made first contact with the Federation, Picard tells them they're lucky they didn't get the Borg instead.
From Voyager episode "The Omega Directive:
Tuvok: What about the Prime Directive?
Janeway: BWAHAHAHAHAHA! Good one, Tuvok.
Tuvok: I'm guessing not today.
It's a great site, I hope you'll enjoy it. But yes, Star Trek universe got pretty fleshed out over time, particularly with DS9 and later TNG episodes.
I really liked enterprise. I'd recommend watching it if you can. It's neat cause it has by far the best special effects and earth isn't an invincible super power in it. They style and doctrine they use feels more in line with today than the other series.
I've watched every Star Trek, so I guess that. I like the whole premise of it, where they're explorers with access to virtually unlimited resources just learning things from other cultures, trying not to destroy everything in the process. It's a very relaxing show to watch. Good way to unwind. Some of the later series' got a little stupid. If I had to rate the different series' I'd say TNG > Original > DS9 > Enterprise > Voyager. Can't wait to see Discovery coming out in 2017 and hope they don't fuck it up too bad.
Never got into the Stargate series'. Where's a good place to start?