I suppose everybody has their own reasons... Mine seem awfully tied up in circumstance that I doubt anyone born after 1973 could possibly understand.
Starting before I was born, in the fifties, the United States cultural consciousness turned to the atom and the Space Age. It was a craze, something young pups can't really latch onto fully - you'd really have to have lived through it, or have something similar today to compare it to.
Human Beings were leaving the Earth. It was like.. new Columbus. Mercury. Gemini. Telstar. Sputnik. That first line in Star Trek - "The Final Fronteer" - really meant something back then. To put this in some kind of perspective, Wild Bill Hickock's "Wild West Shows" were only 18 years older at the time than TOS Star Trek is now: we went from Bows and Arrows to Spaceships in a little over fifty years.
And yes - you need to be at least fifty years old, or close to it, to appreciate how short a time that really is.
The earliest television broadcasts were filled with space adventures. "Space Patrol" ran from 1950-1954, with episodes six days a week and two radio shows, along with a series of comic books. "Tom Corbett, Space Cadet" ran from '50-'55, with television and radio shows, comic books, a regular book series, viewmaster reels... I could give you a whole run-down of the decade, but you'll have to wait for that - it's in the works elsewhere.
"Star Trek" was for the children of the kids who came up with that culture. We were the Apollo Age - we weren't only going up, we were actually going there - Man on the Moon, going "where no man had gone before." The entire country was as batty about space travel as the members of this board are with the "Star Trek" franchise.
We had few options; "Lost in Space" which, towards the end of its run in 1968 dealt with Buddy Hackett (an old-time famous comedian - think Jim Carrey) in a carrot suit rebelling against vegetables being eaten, Hells Angel bikers on space motorcycles, and Hippies that turned the cast into beaded, slang-talking, pony-dancing stereotypes.
And then there was "Star Trek."
At six-ten years old, with an Apollo rocket on the pad and the moon in our grasp, this was our future - what we could be. We were perhaps the last true innocent generation, pre-Watergate, pre-Vietnam backlash; America was the shining light, fighting for freedom, and Kirk's forays past the prime directive made sense to us - we're fixing you for your own good.
At the same time, it was not a perfect age. As Nichelle Nicholes is quick to point out, Uhura was the first black person some of us saw on TV. And, for those of us young enough, it made perfect sense. A lot of that stuff seen today as hokem shot into our brains like silver back then. When us kids watched Kirk lecture Bele and Lokai (the half-black/half-white guys) that they were essentially the same, and all their hate was doing was destroying each other, we didn't know who Martin Luther King was, why he died or what he did one year earlier... but we Knew kirk was right. And that carried forward with us.
As we got older, what the show held became richer for us - we grew into it, not out of it. Some shows we discarded, of course. But many became object lessons in a rapidly changing and disintegrating world. Nixon was thrown out of the highest office in the land, the police were shooting at protesters... but the brightness we had as kids, and the lessons we grew into from the show as we understood it with maturing minds made it more... special, more singular to our experience, and more precious when it was taken off the air.
Sometimes, what you get from something is its ful worth. Sometimes, its what you put into it. There was no replacement for "Star Trek." From 1969 until the late-seventies, there was nothing on TV for space-opera fans. So we made it ourselves. Thousands of fanzines cropped up with new Star Trek stories. Conventions sprung up around the country. It was the Internet, by pony express. If you haven't lived before the Internenet, you can't grasp the enormity of effort put forth by the fans to keep the show alive past its time. A little knot of fans in Ohio would type up their own stories, run off 100 copies, and mail them across the country. Another knot in Pennsylvania would whip up their own, crank 'em out on a mimeo machine, and send them out. A group of fans created a clearing house of fans, for fans, so you could find these fanzines and fan clubs. No corporate funding. No sponsorship. In the end, this net of steel, this bond of determmination and love got the United States first Space Shuttle named "Enterprise."
Why do I love Star Trek? Because it entertained me when I was young, taught me when I was older, and I and my thousands and thousands of unknown friends kept it alive when it was dead to everyone else. Until the rest of you caught up. We've been through death and life together.
The crew got older; we got older. And then they retired, in "The Undiscovered Country." and so did I.
But then... I had a son. And he is ten. And He now plays with a phaser instead of a lightsaber. And he wants to be Captain Kirk. And he thinks the whole hokey action thing is the best thing since sliced bread. I don't know if this new Trek will teach him like the old one taught me - I hope so. But gallivanting around the galaxy is a game for the young, and I'm glad he's got his chance to sign on with the best, most storied, hardest fought-for crew in the history of Science Fiction.