Star Wars / Visual Effects Of Awesome

The Star Wars saga is filled with wonderful effects:

Original Trilogy:

The original and the best, the opening of A New Hope.
The AT-ATs in The Empire Strikes Back.
Speaking of Empire, say hi to Darth Vader's new ride. Rebel pants-soiling ensues.
These days it's more obvious that the Yoda from The Empire Strikes Back and Return of the Jedi is a puppet. But what a puppet! Star Wars special effects have become somewhat dated, but even now they don't hold up terribly at all.
- It should be noted that at the time, there was actually a small movement that attempted to get Frank Oz nominated for an Academy Award for his performance as Yoda.
- You think Yoda was an impressive puppet? If you're looking for an impressive puppet in the original trilogy, look no further than Jabba the Hutt! His huge size makes it much easier to believe he's real, and the actual puppetry works well, too.
While the space battle in Return of the Jedi is impressive on its own, it becomes a thing of beauty when considering that every single ship on screen is a model, the incredible sense of scale created with these tiny little things. Even more impressive is the fact that the Star Destroyer models were around 2.5 meters long — and moved smoothly.

Even if most fans ended up disliking Jar Jar, he was still the first major character in a live-action film to be animated entirely in CGI. General Grievous also has a lot of detail put into him (you can even see his heart beating when he prepares to attack Obi-Wan!).
No Clone Trooper suits were built for Episodes II and III. Yes, they're all Serkis Folk. The effects are that realistic!
The opening sequence of Revenge of the Sith. Calm flyover of a lone Star Destroyer, two fighters appear, then just as they look down below the Star Destroyer, WAR! In a long take, you have two fighters winding their way through a massive warzone. The juxtaposition of sedate view vs. intense warzone is a reminder that Lucas is a hell of a visual director. And did you know that the minutes-long battle between Anakin and Obi-wan took over 700 days to complete? And it was wonderful, wasn't it?
Much of Count Dooku's saber duels in Episodes II and III featured a body double for Christopher Lee with his head composited into the shot. In fact, his part in Episode III was filmed at a different time than Ewan McGregor and Hayden Christensen's, but you'd never know it in the final film because the compositing and editing is absolutely seamless.

The brief sequences from the trailer look absolutely stunning. Even more impressive is that most of the effects are apparently being done practically rather than the CGI approach of the prequel trilogy. Special mention to the Millennium Falcon dogfighting with some TIE fighters.
Another mention goes to BB-8, who is a controllable practical effect as proven at Celebration Anaheim 2015. Most of the shots were puppetry, but remote-control electronic BB-8 models have also been made fully functional and independent.
The muffin Rey makes. She puts the mixture into a bowl right in front of the audience's face, and while the audience is distracted watching her in the background the water seamlessly forms into a muffin. None of that shot was CG.
Maz Kanata is very good motion-capture that really brings her to life.

K-2SO looks so incredibly realistic it's very easy to forget that he is completely digital - in a movie that has quite a lot of Practical Effects robots and creatures, put the digital K-2SO next to any of the others and you wouldn't be able to tell the difference.
The appearances of Peter Cushing, who has been dead for over twenty years, as Grand Moff Tarkin, and a forty-years-younger-looking Carrie Fisher as a young Princess Leia, thanks to some ridiculously good CG/motion capture. Some people have claimed they fall into the Unintentional Uncanny Valley, but they're nonetheless stunningly realistic-looking. If you didn't know they were CG, you probably wouldn't be able to tell their parts weren't filmed forty years earlier. Even Carrie Fisher herself thought it was actually her and that they recycled a deleted scene she didn't remember filming.
The battles in general are gorgeous, some of which is down to some excellent cinematography but a lot more of which is down to ILM's usual fantastic effects work.
The Death Star's power is given a minor test in this movie, leaving behind a massive explosion with waves of debris. In the words of Director Krennic, "It's beautiful."
When a Hammerhead corvette forces two star destroyers to collide, the blade of one shearing the conning tower of the other right off, scattering clouds of debris everywhere. Seeing the painstaking detail put into the 3D models just so they can be slowly torn apart is immensely satisfying.

Out of the shadows, motion-capture Snoke looks completely real despite his obviously impossible features.
The thala-siren milked by Luke was a practical effect, but the puppetry and detail are so good that it's not only hard to believe that it's not a real creature, but also that it's not CG.
Admiral Holdo's Heroic Sacrifice by ramming the Raddus into the Supremacy at lightspeed. Snoke's massive Mile-Long Ship is split in half in a flash of blinding white light and absolute silence.
Yoda's triumphant return, portrayed by an actual puppet!
- Yoda looks exactly like he did in Empire, to the point where it's a little unnerving. There's a reason for that. The filmmakers tracked down the molds used to create the original puppet. They even found the woman who PAINTED HIS EYES just for the sake of 100% accuracy.