Personally, when I was new to reading, I liked the DK Books reference books for their pictures, and also enjoyed the Hank The Cowdog series. For mystery, I'll recommend Encyclopedia Brown, because it actually requires reader participation.

As far as horror goes, I'd recommend The Hellbound Heart, because Clive Barker is a genius when it comes to suburban horror, and exposing the sinister desires that fester in the hearts of the repressed.

None of these statements was false, but only one of the recommendations was genuine; I'll let you guess which.