Read all of em, and I just love em, their my favourite book series I have read so far, can't wait for the fourth book!
Might re-read them while waiting for it actually... I also love the fact that Christopher was only 15 years old when the first book, Eragon, was published.
Favorite part is hard to say.. but I do love the way he defeats Durza in the first book.. as well as the elf-transformation in the 3rd...
Some Roran-parts are among my favorites as well, but the Nasuada parts are kidna meh imo. Something else I like is the way I picture Brisingr, the sword.. Gotta love the fact how it sets itself on fire when Eragon says it's name!
About the movie based on Eragon, they missed out on so many details as well as pretty much re-wrote alot from the book to make it shorter which, in my opinion, made it very bad compared to the book! But that belongs in another topic I believe...
EDIT: Inheritance (the fourth book) has now been announced the other day, release date is set to November 8