I am pretty sure he could read quite a few longer chapter books already, but he's definitely not interested if it doesn't have an ample supply of illustrations. I'll be trying out some of the books on Brandy's list for E. as we go along and may ask advice of some mothers in my homeschool group for quality books that will nurture his soul as well as help develop his reading skills. (Extra points if it can nurture my soul, too.)
I know it seems like I haven't put a lot of thought into what books he'll be reading to me, but the truth is I've thought a lot about it without reaching any great conclusions. I think I need to listen to him read (and really focus on his reading) and then see where that takes us in terms of skill level. We also have a very large collection of books here in the house that he can read to me, so we will not suffer for lack of something to read.