The Witcher games are pretty impressive. Characters have distinct voices and attitudes, and the games are able to present various philosophical quandaries and personal relationships without resorting to tons of verbiage.

KOTOR 2 is the first thing that comes to mind.

Then the Last Express and the Last Door (Season 1) shortly after

and finally Portal 1 & 2 and POP Sands of Time.

Then I remember Shadowrun Dragonfall and realize it should have been the first thing I thought of.

Oh what the hell lets throw in To The Moon.

I've been replaying The Witcher 1 and I had forgotten there are so many good things in that one. In fact, the only thing I remembered that bothered me was the last Chapter, it will be interesting to see if it bothers me now. One thing I can't handle though: Zoltan's eyes. They give me nightmares. Then again I enjoy nightmares..

I was also pleasently surprised by Arcanum.

Then there's non-RPGs that have fantastic atmosphere due to setting, pacing and writing: Mark of the Ninja for example. I haven't completed Transistor but it has something I would call vague story telling, one that I really enjoy.

I think instead of asking people random name dropping I think you should zeroing in on what exactly you think you need to learn more about, that way you will get specific answers.

PS:Torment - It has every bit of the writing done superbly: dialogue, descriptions, characters, settings, plot, themes, everything, and could very well be the best script, but, let's say it's not and ask what else is there that comes close?

Two, actually, and probably more that I don't know (I've never gotten to play Vampire:...)

Interstate '76 - If you like great writing, I'76 is a must-play/experience. Excellent dialogue, story, characters, and voice-acting to pull it all off. It's tight, unique, emotional, action-packed, friendship, has-it-all, sort of classic, imo, done superbly.

Inquisitor - Again, SUPERB writing all around. Epic-literary-novel-esque type stuff. Dialogues, characters, stories/plots, themes, settings (from the overall world and what is going on to the varying locations, etc.) CHECK IT OUT!!! Play it on easy, read up on tips, get prepared for potion quaffing and some bugs and PLAY IT.

I think those 3 ARE better than Arcanum, just ever SO SLIGHTLY, as fucking superb as Arcanum is too, it's a 9.9 if the above 3 are 10s (for quality of writing/awesomeness of what the writing pulls off/delivers.)

Deus Ex GOTY

A lot of things said about government and mega-corporations and mass-media in the game is actually true.

The script of the game was way ahead of its time.

Wanna know how pathetically easy it is to control people using television and mass-media, just play the game.

Planescape: Torment, Undertale and The Longest Journey got the best scripts I've seen in games. Pillars of Eternity is a contender, but it's a bit exposition heavy (which is kind of a necessary evil for an Infinity Engine-esque game) and lack of focus on the characters.

The Freedom Force games. These games completely succeed at what they set out to do, which is to present an affectionate satire of Silver Age Marvel comics. "All I need is a spaceship...AND COURAGE!" There are lots of really good writers that try to capture Stan Lee's scripting style and just about all of them fail horribly, but Irrational actually did it pretty well.

Sam and Max Hit the Road. Arguably the funniest game ever. "Where can we put this bomb where it won't hurt anyone we know?" "Throw it out the window, Sam. There's nothing but strangers out there."

A lot of Tim Schafer's work is consistently funny.

Again with the comedy, Barkley: Shut Up and Jam Gaiden has a ton of hilarious writing in it. The save points, with their insane rants about the supremacy of JRPG design, are brilliant by themselves (although maybe those shouldn't count because a lot of them were supposedly taken from actual websites...).

Nope, I just want to hear what games you guys hold in high regard script-wise and take notes :D

Alright.

Snatcher and Policenauts were made by Hideo Kojima, and are pretty good. It helps that the game around the story is suited for storytelling, unlike the Metal Gear series where there are many pauses to the action. There is a game called Read Only Memories on GOG that was inspired by Snatcher, and is a good play.

I recommend checking out Star Trek: 25th Anniversary and Judgment Rites. They are very true to the portrayal and premise of The Original Series. These games expand upon the source material in a way that seems very faithful, to the point that I consider them to be a fifth season of TOS. You can get these two games on GOG.