There are so many amazing changes I loved, I don't think I can list them all!
In ANH, it was wonderful to see Han fire only in self-defense, making him seem less like a bad guy! That added such depth to his character and showed there was really good in him all along.
The Jabba scene was also a great idea! Not only do we get to see Jabba extra early so we don't have to wait so long to see him in ROTJ, but the important dialogue from the Greedo scene is reinforced and repeated so that we don't forget that Han has to pay Jabba lots of money. That is important for ESB and ROTJ, otherwise people would probably forget why Jabba wanted Han. But not only that; the new Jabba was created with pristine, state-of-the-art CGI and looked just like the puppet!
The ring around the Death Star explosion really added power to the scene and was so much more satisfactory than the old, pathetic one which really looked like a model blowing up (but now it doesn't because of the ring!).
I also really loved the nice blue tint they put over everything, as that added so much colour and atmosphere to the movie.
Also, it looks like Obi-Wan wears lipstick a lot, which I think is a clever nod to the transgender community, showing Lucasfilm's acceptance of all people in the fan community.
In ESB, I was glad to see that the wampa got more screen time. The poor guy hardly made an appearance originally, but now we get to see him eat, confirming our suspicions that he actually ate the tauntaun. With its previous ambiguity, we didn't know what happened to the tauntaun or why the wampa took Luke, but it is all put to rest for once and for all (for all because that crappy original original trilogy is gone now).
I was pleased to see that Boba Fett's stupid voice was finally gone, and replaced by a real actor. The new one sounds like he's half asleep, which works really well with Fett's character, since it shows that he is bored and is so cool he doesn't even care about what's going on.
Vader's new line replacing "Bring my shuttle!" is so much better. With the old line we were left wondering, "Where is Darth Vader going? Will the people on the Star Destroyer be sufficiently prepared for his arrival?" Now everything is clear and we don't have to worry about it anymore.
Another change that I liked was the new Emperor/Vader scene. Now we don't have to deal with Clive Revel and Elaine Baker and we have the handsome Ian replacing them...and with brand new dialogue that explains things better for the fans!
Hoth looked really did look cold with the new blue tint (everything else looked cold too, but whatever).
In ROTJ we are treated to an all new music video called "Lappy Neck" or something like that. The talent and CGI displayed in the video was so good that I think they should go back and replace Star Wars with a musical saga, replacing all puppets with CGI and adding a whole bunch of new ones who can pop out from behind trees and stuff and sing (I can see it now: Star Wars: A Musical Hope followed by The Tenor Strikes Back and Rehearsal of the Jedi and preceded by The Phantom Vocalist, Attack of the Notes, and Remix of the Sith).
I also love the new ending! Now we get to see Naboo and see that our beloved Gungans are OK and we can finally dispel the former notion that the collapse of the Empire was actually spread out over a long period of time. Now we know that everybody was happy as soon as the Emperor died, so the Empire couldn't have been that bad after all, giving us more sympathy for the Imperials when we watch the movies again.
Perhaps best of all is that we get to see the tender young Anakin Skywalker, with the appearance of our beloved protaganist from the prequel trilogy, whereas before that scene was a "Who the heck is that guy?" moment, which detracted from the emotional impact of the scene. Now we see more clearly the tender love between father and son as young Anakin sheepishly smiles at his son and all former misunderstandings fall away. What better way to end the saga?
Overall, I am glad that Lucas just added a bunch of stuff without changing the story and keeping all the continuity errors and other stuff intact. Even better, it is really noticeable so that we don't miss any exciting new stuff and we don't get the original and the special editions mixed up.
May your midichlorians multiply and good luck come on the backs of rontos!