Diane Duane’s Young Wizard’s series.
Starts with So You Want to be a Wizard -I really like these.
And on preview, it’s been mentioned already. 
Anything by Terry Pratchett is brilliant. If you’re leaning more to kid lit, go with his Bromeliad Trilogy- Truckers, Diggers, and Wings. It’s not witches and wizards, but it is fantasy/sci-fi, and it’s amazing. Also in kid lit are some of the books set in Discworld (3 about a young witch; one about The Amazing Maurice and His Educated Rodents); the rest of Discworld isn’t kid lit, just amazing.
Not really witches and wizards, but the Edge Chronicles by Stewart/Riddell are my favourite. Then there’s Spiderwick. Again not w&w, but in the ballpark
These are all really great!
I’ve put in requests via the library system and shall see which comes in first.
Harry Dresden looks interesting…
Butcher is one of my favorite authors right now. He has a more traditional fantasy series that is quite good too.
Dianna Wynne Jones thirded.
If you want a series, then the Chrestomanci books. Many of the others - Eight Days of Luke, Dogsbody, and particularly The Ogre Downstairs are extremely fine fantasy.
If you want something a bit more adult, try George R. R. Martin’s A Game of Thrones. Warning: the series is unfinished…but it’s really good.
I’ve found the Aragon series quite enjoyable.
Do you mean Eragon?
Why yes, I did! Either way, still a fine series.
I’ve said it here before, but I believe that* A Wizard of Earthsea * is the most perfect fantasy novel ever written. Not necessarily the best (although it is very, very good), just *perfect *: no word is extraneous, no paragraph is out of place. It’s shorter than the prologues of many fantasy volumes, and it contains more than most series.
I ducked into the library today and found the first installment of Bartimaeus triology! ( Oh rapturous joy!)
Now, if I could get my children to leave me alone so I can get into the book. or I suppose I could read it too them…
I’m into the first three chapters of it and decided I like it quite a bit, but it is too above the heads of my kids to read right now.
schweeet!
At least three webcomics I read took time out from their usual stuff to plug Name of the Wind. That got me interested. Sadly, it’s not available on Audible yet, which is how I get my books these days. Not much sitting-and-reading time. I’ve got a plane trip coming up, though, and between the Dresden books and Name of the Wind I think I’ll have more than enough to satisfy me.