This is a hard one to answer, because different performances by the same actor have varied from movie to movie. For example, in my opinion Lucy's acting was great in LWW, tolerable in PC, but devastatingly cheesy in VDT. Edmund's acting, in my opinion, was rather weak compared to his siblings in LWW, but grew and changed dramatically in PC. It could be age, it could be directing, I'm not exactly sure, but I can't really say there has been one outstanding performance that has remained outstanding throughout the "trilogy" (at least, the three books that have been filmed). All, that is, but Aslan.
I think the character of Aslan was drastically downplayed in both PC and VDT, and I likewise am inclined to conclude Aslan's CGI degenerated from LWW on. (He does not show nearly so much expression as we see him demonstrating in LWW). However, his presentation, his acting ability, his presence and diction started and finished with so much power, dignity, and honor...it's really just outstanding! There is just something about Liam Neeson's voice that blows your mind! It is so calm, so deep, so reassuring, and yet so full of power and authority! And that voice stays the same all throughout the three films. So I would definitely go with Aslan!

I voted for Georgie Henley as Lucy.

I think she embodied the character perfectly. It really is as if the character simply walked off the page and into the film. Plus, her acting is superb. The expressions, line delivery, etc. is up there with all the rest of the actors, and sometimes even surpassing them. An amazing feat, considering she is the youngest of the main actors in the film.

~Riella

I agree about Georgie Henley. She did great in the first two movies, but her acting seemed a bit weaker in VDT. A lot of times she seemed to be just retelling the script. Of course a lot has to do with the directing. And because the directing was pretty weak, the acting came out a little weak.

A serious toss up between Skandar and Will in their roles as Edmund and Eustace. Both were fantastic. I loved the growth that Ed had in PC and Eustace was just about spot on.

Oh yes, Will Poulter did an excellent job. As I said somewhere earlier you go from being annoyed with him to adsolutly loving him. And since in the movie the actor grows up, it really seems like he grew up and matured after turning from dragon to boy. It was a little cool thing I noticed

I voted Georgie. I actually have problems with her performance in PC and VDT, but I feel she pretty much carries LWW on her little shoulders. When Lucy first enters Narnia, it's just as magical as it should be, thanks to her phenomenal acting. Her acting kind of set the bar and the tone for the rest of the performances in my mind.

I also really enjoy Anna, James McAvoy, and Skandar, in that order. Anna's the only "kid" I can't ever find fault with performance-wise, but her character isn't as important as Georgie's. Otherwise, she'd be my top choice. She also made me love and respect Susan's character. Maybe I should've voted Anna. Oh well. Too late.

I voted for James McAvoy. What a tricky character to pull off, especially with the modern feeling of squeamishness ("stranger danger!") but McAvoy somehow managed to bring the whole thing off perfectly, I think he really did justice to Lewis' character.

If I could vote more than once, I would vote Tilda Swinton for the White Witch, and Skandar Keynes for LWW Edmund. (unfortunately they butchered him in the other movies)

I vote Georgie Henley as Lucy mostly for her performance in LWW she was vary much like the Lucy in the book she fit the role perfectly she was good in PC to but her acting was sort of weak in VDT