One series that we have recently found and love is Stink (Judy Moody's younger brother) by Megan McDonald. We actually started with a Judy Moody book (which we also loved) and while at the library looking for another one, Elliott found the Stink books and decided to try one of those instead. He started reading it in the car that day while we finished up errands, and by bedtime that night, he had almost finished the book. There are just over 100 pages in the books, so that's pretty impressive. He's now working on reading his third one, and we just ordered two from Scholastic, and he found one for $.50 at a thrift store that he hasn't had a chance to read yet.
Elliott really like Stink and Judy both. He likes that they are regular kids and funny. He's really liked both the Stink books he has read, along with the only Judy Moody book we've read so far. I haven't actually read an entire Stink book myself yet. Like I said, he started reading them independently, and hasn't chosen them as read alouds at all. With Judy Moody, it was one of the books that we read out loud together, taking turns. So I don't really have a strong opinion on Stink, but I did enjoy Judy Moody, and found it a good fit our family. There are several books that are aimed at small children that I think really have to be talked over after he's finished reading them, to discuss why we don't model certain behavior, treat our friends certain ways, etc. I didn't feel like we really needed to do that with the Judy Moody book we read.
Scholastic says that Stink and Judy Moody are both 3-3.7 reading level. Stink appeals to grades 2-3 and Judy Moody appeals to grades 2-4.
Elliott discovered the Victory School Superstars series at school. The one above is the only one he's read so far, but he would really like to read the rest of the series as well. He liked that even though Josh wasn't good at soccer, his friends helped him to become better. He learned that it's important to concentrate on what you are doing at the time, instead of what you wish you were doing as well.
This series also has reading levels ranging from 3.0-3.6. It appeals to readers in grades 1-3.