Many good ones mentioned such as the first Fallout, New Vegas, and Bioshock.

I personally like the new opening cinematic to https://m.youtube.com/watch?v=t_wWnLUgXvc for being so visually stunning and downright brutal.

https://www.youtube.com/watch?v=HdEthjXZg_Y

One of the best games of all time...and this cutscene still takes me back.

Arkham City: https://www.youtube.com/watch?v=muCtJsy-d9w

Witcher 2: https://www.youtube.com/watch?v=pStcJ7QB8_Y

The intro to "https://www.youtube.com/watch?v=4DOKzTHaPfM" I still find it amazing today.

The Witcher 3: Wild Hunt Launch Cinematic https://www.youtube.com/watch?v=VF7kqc7th0A

I love the first part of Supreme Commander Forged Alliance intro video, i always watch when starting the game:
https://www.youtube.com/watch?v=aO23gaouvjQ

This was a cutscene in World in Conflict that was also used as a trailer and I always thought it was fantastically done:

https://www.youtube.com/watch?v=4hjnl5gDgCM

https://www.youtube.com/watch?v=q09quI356sQ The game delivers what that intro promises.

In-game: Morrowind tutorial intro :> "Wake up!"

https://www.youtube.com/watch?v=PjqsYzBrP-M

https://www.youtube.com/watch?v=yPq_NVi-TC4

This is my most memorable trailer by far. I didn't add it because I initially read "cinematic" but I noticed that this topic allows trailers as well!

https://www.youtube.com/watch?v=a3ZGGIdpfEM

Aw, this trailer gave me the goosebumps when I first saw it. The Halo trailers have always been some damn memorable ones. Even some of the live action ones.

Gonna go back to my childhood favorite. https://www.youtube.com/watch?v=aVEeGtO0Px4

Halo had one of the most badass /memorable music intros ever! First that choir then a badass guitar riff oh man why did 343 change it?

Been gaming 30 years, no intro have ever come close to this -

https://www.youtube.com/watch?v=lFiLNc46jAM

Not really the best intro, but I recently rediscovred the game, and I think it is not that bad all things considered ( intro that is, the game itself is so-so to be honest).

https://www.youtube.com/watch?v=X8QXXB1Kt3E

https://www.youtube.com/watch?v=KKEvLcA0JOQ

It breaks my heart to not see another LoK game after so long. The multiplayer 'Nosgoth' game on Steam doesn't count.

https://www.youtube.com/watch?v=njMK04xlSf4

These are the closing days of the 3rd Era, and the final hours of my life....and then the music picks up with a fantastic view of the city..if you dont know what Im talking about then you werent apart of the adoring fan club.

Hmm yes, that was pretty good. Seems like every other game of Beth's had very subdued openings. Well apart from Redguard. I played the GOG release recently, it did have quite an uplifting score to the opening credits. And it was nice seeing MK's name get pride of place in the list of dev names.

Ah, man. And that horn section.

Good but no Reaver.

Threads merged.

FFIX has one of my favourite intros. https://www.youtube.com/watch?v=IBw_TX63TZQ

Although I guess it's mostly because of what we learn later that makes it so epic.
The whole game is full of great ones..... now I need to replay it!

Actually, the intro to 8 is also great... https://www.youtube.com/watch?v=q09quI356sQ

Intro to https://www.youtube.com/watch?v=Wz3ufaZCoVw

I remember being very impressed by the intro to the https://www.youtube.com/watch?v=lkRuJWOyVcU, interesting to see how graphics in the series have improved since then.

I remember the trailer for the original KOTOR was awesome. I remember watching or hearing this https://youtu.be/9kDFNFLOLCM?t=461 while shopping at gamestop.

Ive always loved the https://www.youtube.com/watch?v=N37fg0cU63k version.