I thought The Wizard's First Rule by Terry Goodkind was ALOT like Eragon, very similar plot, but extremely good.
I think someone else mentioned Tamora Pierce, she is a MUST READ, I personally recommend her Circle of Magic Series to all my friends, and I've never gotten a negative opinion about them.
Emily Rodda is my favourite author, mostly cos she ties the plot together so well and I love the riddles, Deltora Quest series and Rowan of Rin series are fantastic.
The Rangers Apprentice Series by John Flanagan is great, not really based on magic but set in the same time and you'd have to call it fantasy. Someone described it to me like that and I kinda thought "nah, no magic, not my type of thing" but I LOVED it.
Isobelle Carmody's Obernewtyn Series is amazing, a fantasy set in the future and it not only has a good plot but some interesting concepts too.
Trudi Canavan has written two good series, The Black Magician Trilogy and the Age of the Five trilogy. In both, it is really hard to get into them, the first books are so boring, but once you get into the second things start picking up and you'll really enjoy it.
Well the books in my Answer alone should last you at least a month (if you read at my rate) not to mention everyone else's Answersso I won't go on! Good luck, enjoy your reading!