7 is old enough to move into chapter books imo. 2nd grade was when i, as well as my friends, progressed into boxcar children, nancy drew, hardy boys, and goosebumps. if you want to kick up the storytelling a notch go for the roald dahl books. maybe if they’re especially precocious you can go for the longer chapter books like beverly clearly or even the always controversial Judy Bloom.
however, i will say the 3 books that made a huge impact on my life specifically are 2 mythology books, both by Ingri D’aulaires, as well as a worn copy of a history textbook from the 50s that was serendipitously picked up from a neighborhood yard sale. those three books taught me SO much. i mean, history and myths are stories - plain and simple. they stimulate the imagination and develop a sense of awareness of the world that i think is invaluable.
the history book especially, was written as a serious of short historical novels that followed specific historical figures like they were characters in a novel. for example instead of learning about “egypt” it narrated imhotep and told the story through that context. instead of dry facts about Crete, it told of how Minos came to power and “discovered” smelting bronze when he accidentally bought a chunk of tin from spaniards because it was shiny.
and as far as i can figure:
http://www.amazon.com/Story-World-History-Classical-Earliest/dp/0971412901 is a close modern approximation of what i was reading.
i read a lot as a kid and just remembered some other books that delighted…
wayside schools book series
wrinkle in time
cam jansen series (girl version of encyclopedia w/ photographic memory)
EVERY SINGLE CHOOSE YOUR OWN ADVENTURE BOOK…
and i think i read my first Redwall book by the end of 3rd grade