We have a few favorite series for DD6. She plows through these books like there is no tomorrow, only to reread them again and again and again...

The Pony Crazed Princess: Princess Ellie Adventures about a princess who would rather be with her horses than be a princess by Diana Kimpton

The Disney Fairy Stories, about Tinkerbell and all of the other fairies that live in Pixie Hollow.

Ivy and Bean Series by Annie Barrows and Sophie Blackall about 2 7 yr olds (I think they're about that age) who are neighbors and get into all sorts of mischief together.

And she recently started the series by E.D. Baker With the books Frog Princess and Dragons Breath in it. These are about a princess who kisses a frog to turn him into a human and she ends up turning into a frog instead. DD was laughing out loud when she read these two books, so I'm sure we'll be getting the rest from the library soon.

When she needs a break from these she reads the Berenstain Bears chapter books, which are fun to read.