Even though I think overall TNG was the best written and most memorable of the shows (yes, I grew up in the 80's), my personal favorite is still TOS. I also grew up watching reruns of Kirk & co. on my family's little black & white set. When we finally got our color TV I was shocked and amazed by the bright colors of the uniforms and set!
It's always been the most fun, even if the special effects are outdated and the 60's style a bit cheesy (not that the 80's style of TNG hasn't gotten cheesy by now already), and it's episodic, the characters are likable and there's always some action, imagination and fun to be had.
The "Star Trek Remastered" is a little jarring for some fans (see our own fandom's controversy with the "Special Editions") but overall I think most of the changes they've made are subtle enough that they don't ruin the show (since in each episode we got the same half dozen shots of the Enterprise orbiting a generic planet that was just a different color... and now with CGI they're all unique)... and the new Blu-Ray sets apparently have both versions so you aren't missing anything.
DS9 didn't feel much like Trek for me, but got better in its 3rd season. The final season (7th) felt rushed and a lot of people didn't like it, but overall it wasn't a bad series, once you got into it.
Voyager was just as bad as everyone said, though it started out pretty promising (the first season wasn't that bad, and had a lot of cool ideas though Janeway seemed like an awful captain). A lot of people thought the show got better once Seven-of-Nine was introduced, but sadly this felt more like an act of desperation (get an attractive woman into a skin touch outfit to strut around to distract you from the bad writing and cheap effects). The show really went downhill by season 4 and the finale was utterly awful.
Enterprise started out with a lot of promise (though we all wondered what the point of making a Prequel is if you're going to run roughshod over the established continuity... right George? sorry, wrong topic), and I actually was enjoying it at first, but part way through season 1, when they got that episode called "Dear Doctor" (I think it was the 12th episode) I really started to hate the show. The "moral" of that episode was frankly offensive, and just seemed totally out of character and just plain stupid. The third season had a radical change, but it just didn't feel like it was going anywhere worthwhile and the climax was completely unsatisfying. The characters were dumb, and it just felt too much like a copy of Voyager, sharing many of the same failings. I probably liked Enterprise more then than I did after watching Voyager, and seeing how one show cribbed off of the other. In the final season, after the first two episodes (which clumsily wrapped up the stupid "Temporal Cold War" plot in an unsatisfying manner, with the laziest plot device ever... SPACE NAZIS!), it started to get better, and I actually thought the rest of Season 4 was pretty enjoyable, compared to what we'd been seeing in Trek for the last several years. But the season finale? Utterly abominable.
I blame Rick Berman and Brannon Braga for running the franchise into the ground! By the time they handed Enterprise over to Manny Coto in its final season, it was too late to save the show, but he did the best he could with the scraps that were left. Of course B&B insisted on ruining the finale.
The last two Trek movies have been disappointments... Insurrection had a very questionable "moral" to it and just pretty annoying overall, then Nemesis was more of a really bad ripoff of "The Wrath of Khan" that made very little sense.
My expectations for the new movie are low, but I still want to see it. I figure if nothing else, it'll be a SFX summer movie that I can enjoy for a couple hours of escapism at the IMAX.
Sorry for the rant. I'm a fan of both franchises and I just can't stand to see good sci fi wasted like this by the people who ought to care the most about it succeeding (the owners and producers). :P