Personally, I'm into fantasy and science fiction. So if Harry Potter is too "witch-crafty" for you, you might not be interested in my opinions.
However, when I was in middle school I was reading Piers Anthony's X(a/n)th series, it's pretty simple characters and story lines and it's mostly tongue in cheek puns the whole way through. Some of his early books are a little more heavy and some of the later ones are slightly more adult (even PA calls himself a "dirty old man"), but a good majority of them are completely kid friendly.
I was also reading Mercedes Lackey's Valdemarian series. You'll want to stay away from the original trilogy "Magic's Promise", "Magic's Pawn", and "Magic's Price" not only is the story line very dark and heavy, but the main character is gay. It's not graphic or anything, but it's obvious the character and his friend are lovers. Also, his friend uses him to summon demons and then dies tragically causing the main character to create a spell that prevents magic users from coming into Valdemar and summoning demons ever again. It actually sets up a big plot point in the series, but it isn't a necessary read since the plot is explained in later books. If you're an adult and not homophobic, it's a good read, otherwise "not for kids".
The rest of the series however, becomes a lot more commercial and lighter in tone, it's very kid friendly and mostly deals with teenagers finding their purpose and niche in life as they become young adults. The books are full of adventure, magic horses, and learning how to be who you are.
Of course, I was a bit more of an advanced reader at that age. At the same time my contemporaries were reading Babysitters Club, which I just never got into.