I love Star Trek... although not quite as much as Star Wars!
Watched every episode of every series as they were broadcast over the years. Bought Sky originally so I could watch TNG as it was first aired in the UK.
DS9 has always been my favourite of the series. Loved the characters.. Judzia was brilliant, and once Sisko became Captain and shaved his hair off his character took on a much darker side that was great. Odo and the whole shape shifter race was a little annoying, but the Dominion were great.. especially Weyoun. Garak also had a great roll. And DS9 was the one series that expanded the universe outside of the human centric Federation and tried to show the universe from the perspective of other races.
Especially loved the Mirror universe episodes... Mirror, mirror for TNG and Crossover for DS9.
But my favourite DS9 episode had to be "Trials and Tribble-ations". That was just brilliant. Mixing the footage from the Original series with the DS9 actors was really well edited. I especially loved the end when Sisko talks to Kirk on the bridge and Judzia taking a quick opportunity. Also the scene when they are stood in a line and Kirk is examining each in turn is so well done.
Voyager annoyed me a lot, although it still had a lot of great episodes. Some of the characters still annoyed me right up to the last episode. I couldn't stand Janeway or Chakotay... especially the episodes that were focused on him and his vision quests. They were so boring. They could have done so much more with the ideas. Other characters and episodes were still good though. My favourite characters were Tuvok (especially later on), Paris, The Doctor and Kes. 7 of 9 was OK but I also never thought they explored what was possible with her character as much as they might have.
The Next Generation evolved the most out of all the series. It's first series was very different to the last. The sets, look, style, scripts come across very dated in the first series and a lot of the episodes stuck very closely to the style of the Original Series. I much preferred it later on once it had evolved.
I especially enjoyed it once TNG, DS9 and Voyager were all running alongside each other and they started to link the series so you had to watch all of them to fully follow the story and characters crossing over between series for some episodes.
The Defiant was also my favourite ship from any of the series... although you still can't beat the Klingon ships.
As for Enterprise. The first pilot episode was really good and showed great promise for the series, but the actual first series was a bit boring and the characters very wooden. Only once Klingons were introduced and the series got darker did it all start to get interesting and worth watching.
Saying all that, if an episode from any of the series is on TV I will normally watch it and enjoy it. Still love watching the original series too.
Films were great too, and even the new ones. More action orientated but I enjoy them for what they are, rather than these fanatics who get hung up on them not being "in the true style of Star Trek".