Kirk and his merry band ran into a lot of funky aliens on their jaunt. My question is, who was your favorite that you would like to see get a little more coverage?
My pick: The Gorn . I don’t know why, I just loved him. He was big, and mean and I wanted to see more of him. The Klingons were built up as the ultimate warriors, and I always thought the Gorn could clean their clocks one-to-one. Yeah, that’s a lot to get from one episode, but there you are.
The Tholians. The crystal life forms encountered by the Enterprise during the incident with the first USS Defiant. Wierd lookin’ would love to see a non-1960s version of 'em.
Kirk
I grew up with TOS when it was in syndication in the 70’s. I still watch some of the episodes on the Sci-Fi channel, there were more than a few episodes with good storyline and acting. None of the later incarnations wanged my twang in the least. Must every production these days be a PC mouthpiece? Sheesh.
Anyway, as a 10 year old – “The Arena” with the Gorn was waaaay cool… “SSsssss… Captain… I shall be merciful and Quick… Ssssss…”
The “Edith Keeler Must Die” episode was pretty spiffy too, (Guardian of Forever) while not really an “alien” the Guardian itself always inspired awe when I was a youngster.
The “Buttheads” which were played by females, incidentally in the pilot episode sort of creeped me out, later spliced into a regular production two-part episode. Given the series budget, and the state of special effects in the 60’s, they aren’t too bad. Today I watch the show out of nostalgia and partly for the humor, looking for the numerous plot holes and other trivia.
The Organians. They were able to impose a Federation-Klingon peace by fiat, when both sides wanted to keep fighting. I’d like to see them meet up with the Q (but not in the Enterprise series. They’ll have to wait and do it in a movie or series that takes place after the first appearence of these entities).
The Melkot. When the Enterprise showed up, they (sort of)recreated Tombstone at the time of the Gunfight at the OK Corral. Their telepathic and xenophobic ways could make many other interesting stories.
The Horta. The peaceful silicon beings from The Devil in the Dark. In one of the novels (The Romulan Way) there is a Horta in Starfleet. If they joined up back then, they should be pretty well integrated into the Federation by the 24th century.
The Saurians. The only one that ever, as I recall, showed up on film was an “Extra” in Star Trek: The Motion Picture. I always thought they were at least interesting LOOKING. Sadly, these days the only aliens that show up are the generic bump-head-of-the-week aliens, and generic warty-lizard-people aliens. Well, at least “Enterprise” has brought back the Andorians.
The Selay and the Anticans from the early days of TNG were pretty interesting (artistically) too. Snouts and everything.
Ranchoth
(“Ssssory, wrong ssspecies.”)
Let me just put in my two cents here in favor of the Tellarites! 
I am hoping that they will show up on Enterprise, especially as they are among the Founding Members of the Federation. I’m not sure (faulty memory here ;)) if they’ve ever been shown in any of the series or the movies (they may have shown up in one of the movies, particularly in a Federation council meeting scene), but these are the aliens that look a bit … porcine. LOL Come to think of it, there was one in the “Tower of Babel” on TOS, I believe! Anyway, this is definitely one race I’m looking forward to seeing again. Oh, and I would also like to see both the Gorn and the Tholians, although I doubt Enterprise will be the vehicle for either. LOL You never know, though–Brannon & Braga seem to toss CANON right out the window at times. 
my .02 cents
tarragon
The tellarites were in the Federation Council scenes of Star Trek IV, and I believe the bar McCoy/Spock goes to in Star Trek III.
Kirk
The heck happened to them?
Edith Kellor Must Die is “The City On The Edge Of Forever”.
Well, i liked the gold midgets from Journey to Babel, the world needs more gold midgets. But as far as coolness goes, Gorns rule!! (and those funky TMP aliens with big heads and some sort of gas mask, they were just extras, but neat)
Whatever race Clint Howard belonged to.
Let’s play mindgames for an hour and then have drinks!
“This … is tranya …”
Well, I would say specis 8472, but they were in two or three episodes.
There was an episode of Voyager where Tom and Harry I think were mind controlled into fighting this war for a species against another species on the same planet. The ones they were fighting looked wicked cool, but I forget the name.
Whoops, it was just Chakotay, not Tom and Harry. But I still don’t know the aliens name…
here is a link to the episode, with pictures of the baddies (vaguely Predator-like)
http://startrek.com/library/voy_episodes/episodes_voy_detail_69030.asp
Kradin were the bad dudes, the Vori made themselves look human via hypnosis, i think they looked just like the Kradin did (episode on tape is currently in storage)
Umm, Tedster, I gotta point out that TOS was also a “PC mouthpiece”. After all, episodes like those about the half-black/half white aliens pretty much promoted tolerant beliefs in the '60s. It was pretty overt and people ALWAYS bash later incarnations for their overt plots while TOS had the original obvious “moral” plots. TOS was, in essence, Roddenberry’s mouthpiece.
As for what alien, I want to see more of the Guardian of Forever. That’s always been my favorite episode.
Tosk, from DS9’s Captive Pursuit. “I am Tosk, the Hunted.” It was interesting, an entire race that lived to evade hunters as some kind of game. They didn’t want freedom, just to “live to evade the hunters another day.” I always wanted to see a sequel to that one.
The Jem’Hadar were designed to look like Tosk, on the theory that the same race that created them for the Hunters was conscribed by the Vorta to creat the Jm’Hadar.
bouv - I saw that one too, and thought it was quite clever. The races fighting were the Vori and the Kreidan. The Kreidan were the cool looking, infringing on Predator rip off aliens.
Tribbles.
Soft, furry, born pregnant.
Once in TOS. Once in ST:TNG
Tribbles were never in ST:TNG. But they once were in Star Trek: DS9, and they were in two movies: Star Trek 3 and Generations.
Caitians.
Lt. M’Ress was one cool kitty. 
Oh, how I wish they’d give her a Star Trek novel.