This much loved novel came to the big screen ages ago, but I hadnt seen it until watching the Eragon DVD. Comparisons with the might of things like the Lord of the Rings is perhaps unfair, yet it does tread much of hte same ground. Things have none of the same class, yet they are still enjoyable and the CG (esp the dragon) holds up.
The dragon works ok for them here as it is far from human and its interactions with the live actors small. Eragon himself gets to ride all over Saphira, but with a few good shots and plenty of cuts and close-ups it does work. The battle with the shade at the nd on his demonic bat thing is quite fun. Indeed it continues a line of recent dragonish splendour includide LoTR, Harry Potter and Beowulf.
There are several good articles on the CG in the film:
Viewpainting at ILM on CGSociety
Eragon: Conjuring A Compelling CG Dragon on VFX World