And the days that I'm taking about were when I was young and able to read whatever chapter books caught my fancy. I can't rightly say that I actually remember what chapter books I was reading between the ages of 7 and 10. My memory is just not that good. Neither is my mother's, though she should be excused on the grounds that I am the youngest of four children. (Why on earth would she remember that?)
I do remember that she would usually let me choose whatever I wanted for reading material, as long as it wasn't too adult. I was a fairly advanced reader, and I don't remember having a fondness for any easy reading material. My favourite book at that time (around age 6-7) was The Lion, The Witch, and The Wardrobe. I'm not sure if that really counts as a chapter book, per se. It had chapters, yes, but the writing was a bit more dense.
I also loved The Babysitter's Club books. I had quite the collection of them. My other favourite books were the Little House on the Prairies series. So, again, not really chapter books, but I really don't remember being interested in reading those types of books at that age. They seemed too short, too easy, too boring.
I like Babysitter's Club because the girls seemed so much older, so mature. And I wanted to be like that. It impressed me, all the different things they did, and the issues that they went through. Like when Kristy's parents got divorced, or when Mary Anne and Logan broke up. I suppose it was that glimpse into a more adult world that I really liked. The language helped as well I'm sure, not being as easy as books aimed at the 7-10 range would be.
And while Babysitter's Club didn't have illustrations, the Little House books had a few. I did enjoy them, since they usually showed glimpses of such a different world, being set back in the 1800s. But they weren't integral to the story for me. At that point in my reading, I didn't need pictures. They were a bonus for me, because I could use my imagination just fine, and I usually didn't need illustrations as any sort of clarifying point that went with the text to make it clearer.
All in all, I don't remember reading chapter books on my own. I'm sure I did while I was in school, for the curriculum that we had to cover or for little projects. But on my own, I generally chose "older" books, ones that were intended for an older audience.