My preferences:
DS9: This show took a while to grow on me since the first couple of seasons moved a bit slowly. But once they started on the Dominion war arc, it became my favorite of all of the Star Treks. They really did well at addressing tough issues involved with religion, war, and many ethical dilemmas. The character development between seasons 3-6 was outstanding.
TNG - A very close second for me in terms of favorites. I notice many people are saying it is dated, but I haven't noticed. Maybe I'm really dated too
. The characters had great chemistry with each other and the show really held together in a spirit of space exploration that TOS had begun. TNG claims some of the best single episodes of all of Star Trek.
TOS - I love the concept and the main characters, and have read a good number of novels based on this series. But it doesn't rank among my top favorites because it is very dated in special effects and general portrayal of women.
Voyager - It had a very good premise and I want to like it, but it just felt too much like a TNG take-off. Even aside from the problems with Q and with the Borg, they hit the "reset" button way too many times with problems they came across. There was a really good two-part episode called "Year of Hell" which I think should have been a story arc that covered the entire season rather than just a problem-of-the-week. It would have given Voyager some real depth that it never allowed itself to have.
Enterprise - It had so much more potential than it lived up to. I stopped watching after the first season because it was so boring, the first Star Trek I can say that about. I later started watching it again with re-runs, but the show just had a way of ruining everything I "knew" about Star Trek instead of being a decent back-story. I was glad to see it cancelled.
DS9: This show took a while to grow on me since the first couple of seasons moved a bit slowly. But once they started on the Dominion war arc, it became my favorite of all of the Star Treks. They really did well at addressing tough issues involved with religion, war, and many ethical dilemmas. The character development between seasons 3-6 was outstanding.
TNG - A very close second for me in terms of favorites. I notice many people are saying it is dated, but I haven't noticed. Maybe I'm really dated too

TOS - I love the concept and the main characters, and have read a good number of novels based on this series. But it doesn't rank among my top favorites because it is very dated in special effects and general portrayal of women.
Voyager - It had a very good premise and I want to like it, but it just felt too much like a TNG take-off. Even aside from the problems with Q and with the Borg, they hit the "reset" button way too many times with problems they came across. There was a really good two-part episode called "Year of Hell" which I think should have been a story arc that covered the entire season rather than just a problem-of-the-week. It would have given Voyager some real depth that it never allowed itself to have.
Enterprise - It had so much more potential than it lived up to. I stopped watching after the first season because it was so boring, the first Star Trek I can say that about. I later started watching it again with re-runs, but the show just had a way of ruining everything I "knew" about Star Trek instead of being a decent back-story. I was glad to see it cancelled.
