Star Trek. The next Generation and Deep Space 9 especially. Even though Babylon 5 is the better series and the early BSG Remake episodes were genius. The idea of humanity finally getting its act together and exploring the stars (while abandoning money and having people working in their aspirational fields on earth) just appeals to me on so many levels. Star Trek provided much needed escapism when I was a kid. That, and I can think of many good uses for a Holodeck. Full disclosure: I have read hundreds of Star Trek novels, only a few of which I'd actually describe as truly good reads. I only started getting into actually decent Sci Fi when I basically ran out of Trek books.
I've seen all of DS9 and Voyager. I like them because they have overarching plots. Does that happen in TNG or is it all just "monster of the week" type of episodes?
TNG is entirely monster of the week, including the mandatory "See, everything is back to normal" shot in the end. That said, certain themes and characters are explored and revisited throughout the series. If you mainly enjoyed DS9 and Voyager for their overarching plots, TNG probably isn't for you. Its first season was cringeworthy, too. As far as I know, DS9 along with Babylon 5 pioneered the whole idea of having continous storylines along with a main plot throughout their lifetime. TNG came before that. If you enjoyed DS9, the story of Babylon 5 is definitely worth your time. The first season isn't great, but well worth sitting through with the knowledge that it gets dramatically better. You'll have to deal with early CGI, which looks quite hilarious today. In later seasons, the visuals easily surpass DS9's model based shots, though.
You should try to get your hands on some Blake's 7; it's the granddaddy of TV space operas. It might not be the best show out there (it didn't get the budget it really needed), but you can see its influences on the shows like B5 and DS9.