I voted Liam Neeson as Aslan. His rich, deep voice just makes me really think of a powerful yet gentle Lion Aslan is.

I voted Other - my choice is Sergio Castellitto as Miraz.
It helped his performance that his part was fleshed out more in the film than in the books - but he played his role very well. He made Miraz a more interesting character. Not necessarily a more likeable character, he was still a villain - but an interesting villain.

I thought Georgie Henley was good as Lucy. She was sweet and acted fairly well. My favorite scene is when she first went into Narnia, through the wardrobe.

I also liked Edmund and Eustace, who were both good at being annoying and then turning into good characters.

I'm going to have to say Skandar Keynes as Eustace. Remembering all the films, I think his acting is stellar for each one of them. He's perfectly awful before his redemption, but his physical appearance visibly changes after his encounter with Aslan. I think that most of the time in the second two movies, he's had dialogue and certain parts that did not display his skill to its maximum or altered it, which is a pity, because all in all, his performance was great.

Second, I'm going to say Will Poulter as Eustace. It's such a shame we'll never see him as Eustace in TSC, when he'll have a larger role. His acting was my favourite part of VDT. Though I initially could not imagine Eustace and therefore kind of imagined him kind of like Skandar (kind of like Skandar and the boy who played Lucien in Treasures of the Snow), now Eustace will definitely be Will Poulter to me. (except, with black hair, since that's how Pauline Bayne's illustration came off to me. ) His acting as a snobbish, rude child was believable and great and his acting as a changed character was equally believable. I was greatly impressed with his deliverance of the role, especially at the farewell scene.

And Liam Neeson as Aslan, of course. I can't think of what other actor they would have chosen. His voice as Aslan was warm and rich and perfectly Aslan-like.

EDIT:

And I must add Georgie in LWW. She played the part so naturally, responded so acutely to every emotion and every back-and-forth with the characters. She was the most adorable Lucy.

Oh defiantly Liam Neeson as Aslan. From the moment you hear hфs voice everything within you comes to life. His voice is almost magical and you can really feel the power, yet gentleness in it.
Second comes Will Poulter as Eustace. I personally think that he is a very talented actor, and is probably the one of the only things I like in VDT.
I really like Georgie as Lucy in LWW and PC, in VDT I feel that there was something lacking. Her performance wasn't so strong, and there was just something missing.

Though I initially could not imagine Eustace and therefore kind of imagined him kind of like Skandar (kind of like Skandar and the boy who played Lucien in Treasures of the Snow), now Eustace will definitely be Will Poulter to me.

You know, I also imangined him as kind of a mix between Skander and Lucien. I remember when I first read VDT Eustace reminded me a bit of Lucien

Oh defiantly Liam Neeson as Aslan. From the moment you hear hфs voice everything within you comes to life. His voice is almost magical and you can really feel the power, yet gentleness in it.
Second comes Will Poulter as Eustace. I personally think that he is a very talented actor, and is probably the one of the only things I like in VDT.
I really like Georgie as Lucy in LWW and PC, in VDT I feel that there was something lacking. Her performance wasn't so strong, and there was just something missing.

Oh my goodness, yes. I'm just going to ditto everything you said, De.

In addition to what De wrote, I really liked Edmund as well. His performance in LWW was impressive, as he really strove to take on the emotions and feelings of the "black sheep" in the family. I love his dark expressive eyes, as several people from the LWW Movie Companion would agree.

In PC he was good as well. He wasn't quite as dynamic, but his comic timing was great. Also, in LWW we mostly get to see him in his traitorous state, but not so much his redeemed state. However, in PC, he was completely changed, and I loved seeing the contrast to that. The only thing I wish is that we could have seen more of him.

As for his performance in VDT, I'm torn. There were some scenes where I loved him (such as the scenes where they first enter Narnia, and his scenes with Caspian, as well as the end) and some scenes where I felt it could've been better. However, I'm wondering if the lackluster performances were due mostly to the script. I read somewhere once that even the most talented actors can only work with what they've got, and if the script is mediocre, the acting may be mediocre as well.

Tilda Swinton was also fantastic. She took every expectation I had for the White Witch and blew me away. Originally I'd expected Jadis to have black hair, extremely pale skin, and ruby red lips. Tilda Swinton was the complete opposite of that, and yet she was perfect for the White Witch. Her portrayal was chilling. (Ha, chilling—see what I did there? ) Even now, pictures of her without the White Witch garb still remind me of Jadis. She was great.

Also. Mr. Tumnus. He also took my expectations and blew me away. He was perfect, and I adore James McAvoy's portrayal tons.

Overall, I absolutely love everyone in all the movies to some degree.

MountainFireflower, I also agree with you that I love everyone in the movies to some degree. If I didn't like someone in one movie, then I like himher in another movie. I aslo really liked Ben Barnes in PC. I was sooooo sad that they took his accent away in VDT. Grrrrrr
Oh, I remember there is one character I didn't really like at all. I didn't like Reepicheep, not in PC and not in VDT. Somehow the voices just didn't match. But then that's just my opinion

I agree with fantasia_kitty. I love Georgie in LWW; she is so real.
But, in VDT she seems to have a little trouble acting younger than she is, something Will Poulter mastered. So, I picked Will Poulter. I think He really redeemed VDT. His character alone makes me want to see it again. I really liked Eustace even when he was annoying the others.

I voted for Will Poulter, as his acting was the most consistent, and he completely sold me as someone who could almost deserve the name "Eustace Clarence Scrubb."

I feel a bit bad, though, for Skandar and Georgie: were it not for VDT (where both performances were predominately forced or lackluster), I would have picked one of them--probably Skandar for the top spot. They just didn't seem to have their hearts in VDT, which I can't really blame them for...

As to Aslan, he was quite sufficient in LWW, and he hardly had any voice-time in VDT so I can't call it either way there, but I felt that his performance fell flat in PC. *shrugs* Perhaps it was the scene with Lucy in the forest that bothered me the most... He just felt too much like a safe lion, even in the bridge scene, to me.

Hands down Will Poulter.

He was meant to play the role of Eustace and still is. Will really brought the book character to life.

For a second choice, I would choose Will Poulter as Eustace.

He was so wonderfully annoying before his change - and he showed some gradual change, too, as the Narnian world was working on him. You could even hear it in his voice. I particularly noticed when he first saw the magical map on Coriakin's island - there's warmth and wonder in his voice when he says something about it being good or beautiful - and then he remembers what reputation he tries to keep up and adds in a much colder voice, "for an imaginary map of an imaginary world, that is".

And then the change is complete (for all practical purposes), and he manages that transition to a nice guy for the rest of the movie - on the sea of lilies, and on the beach with Aslan, and in his room afterwards.

I really would have liked to see him in SC. I wish it still could be done.

I picked Georgie Henley as Lucy, I think mostly on the basis of her performance in LWW. That portrayal has influenced how I 'see' her character when I read the books or see other adaptations more than any of the others.

Skandar Keynes and Will Poulter were also very well cast, and I liked them in the movies, but I don't think I would necessarily go back to them as a gold standard for the portrayal of the characters. (But I would certainly vote for them if I were allowed more than one choice in the poll.)

This was hard but I ended up picking Skandar. For LWW it would be Georgie Henley as Lucy. I thought Skandar was just right in LWW as Edmund and did really well in PC in a smaller role and was good in VDT.

Wish that I could vote for more than one because more than one actor did a fine job in his/her role.

If I had to pick just one (who wasn't an amazing performer in Narnia?), like fantasia_kitty, I'd have to go with Georgie Henley as Lucy. There is such a natural and innocent quality to her perfomance (especially in LWW) that it's not so much acting as a genuine factor (it is as though we are seeing Lucy as she is, not an actress playing her). For example, at Lucy's first discovery of Narnia - we are not seeing an actress put on a look of wonderment, but rather an actual child with natural curiosity anticipating excitement. You just can't pretend or fake that sort of thing.