I didn't know this, but apparently a few years ago Paramount kicked around the notion of "updating" Star Trek (The Original Series) (hereafter referenced as "TOS"), by giving the show's visual effects the George Lucas treatment. They clearly abandoned this idea, but some prep work for the project was done as a trial-balloon by two different SFX outfits, and you can see portions of their results here and here. They're both clips of the classic episode "The Doomsday Machine". (I prefer the first one, myself.)
For those who aren't geeky enough to know their classic Trek episodes by title, "The Doomsday Machine" is the one where the Enterprise happens upon the wreck of its sister ship, the Constellation, whose crew is dead except for her commanding officer, Commodore Matthew Decker, who is rambling about some kind of horrible "planet killer". Of course, the "planet killer" turns out to be all too real: a gigantic cigar-shaped automaton that does nothing but go around destroying planets and powering itself with the remains. It's speculated that this machine is a doomsday weapon that had been unleashed by an alien race locked in a devastating war, and that the planet killer had performed its job all too well*. The episode is one of the most memorable of TOS: I watched it on a VHS tape I checked out of the library a year or so ago, and it was still absolutely riveting, right down to that classic Trek chestnut of the transporter malfunctioning at a very inopportune moment. (For all the fun-making of William Shatner's scenery-chewing over the years, his matter-of-fact delivery of the line "Gentlemen, I suggest you beam me aboard" is classic.)
Anyway, how do the "new" effects look? Well, it's not as jarring as I had expected. I figured it would just look horrendously bad, but they really seem to have made an effort to stick with the basic look of TOS, and simply provide better-looking planets and some new ship movements and "camera angles" in outer space that weren't possible back in 1967. I remember reading once that the reason the Enterprise in TOS is only ever seen from its right side (think about it, and you realize it's true) is that the electrical wiring that powered the lights on the original model came in through the ship's left-hand side. That's not a concern now, obviously, so you get to see the ship from some really unusual angles. (Unusual for Trek, that is. From the standpoint of SF effects in general, none of this stuff is unusual.) You also get to see smaller effects like the Enterprise's tractor beam, some electrical fires still arcing on the wreck of the Constellation, and the like.
I'm kind of glad, though, that Paramount never went through with this, as it all seems a bit pointless. This stance feels a bit hypocritical for me, as I've never been one to complain much about the Star Wars Special Editions. But Trek TOS never really bothered me in the effects department, and it was the scripts that made the show so good, anyway. I mean, really: "Doomsday" is a great episode regardless of its effects, and other episodes -- comedies like "The Trouble with Tribbles" and "A Piece of the Action", or the stunning "City on the Edge of Forever", which to me might just be the finest episode of a TV series ever filmed -- don't rely on effects anyway.
Now, if someone wants to re-do the effects in Star Trek V: The Final Frontier, that would be fine with me.
* Extra-geeky detail: a Next Generation novel that came out in the early 90s postulated that the planet-killers were devised as a response to, those ubiquitous TNG villains, the Borg. I wasn't wild about that idea; the planet-killer is a lot more creepy if its history is left totally unexplained, and there's something haunting about the idea of a civilization's sole remaining existing artifact being a horrible weapon.