DS5 is heavily into comics, especially Carl Barks duck comics and Tintin lately. He has begun getting more interested in superhero and action/sci-fi comics like Judge Dredd, but I haven't found the time recently to vet the stories, so he's not reading them right now. For non-comic, non-puzzle books he enjoys factual stuff like the DK flat books (we have tons) and the recently discovered Library of Curious and Unusual Facts (of which we have four volumes so far). He greatly enjoyed reading this "Scary Stories Treasury" recently (it's really not that macabre, and some of the stories are quite silly):
http://www.amazon.com/dp/0060263415I believe he also read in the last year "The Mouse and the Motorcycle", some Choose Your Own Adventure books ("The Cave of Time" and "Your Code Name is Jonah" come to mind), and assorted other stuff.
I'm not so good at remembering milestones exactly, nor do I remember just what books he was most into at ages 2-3. His favorite Dr. Seuss book early on was probably "Oh, The Places You'll Go!", and his favorite first readers were "In a People House", "Go, Dog, Go!", and "Big Dog, Little Dog". After that I remember that he got into some of the DK Readers and Step Into Reading series, including on the fiction side principally a line of stories about a young detective alligator called Otto and his Uncle Tooth.
ETA: I think a lot of the early Step Into Reading books are dreck, especially the ones based on children's movies and cartoons, but I remember that our son liked these early on:
http://www.amazon.com/dp/0394896254/http://www.amazon.com/dp/0375824170/
