I remember that my dad told his (current) wife that he thought this book and one or two others were kind of perfect kid's books (unfortunately I don't remember what the others were), and she pointed out that none of the books had female characters, which made him sort of sit and think about things for a bit.

I think it's neat that Bilbo's ultimate act of heroism in this book is also an act of betrayal -- instead of giving the Arkenstone to Thorin, he gives it to the Dale folks, in an attempt to avert a war. It doesn't seem like it would necessarily have actually worked (invasion of the goblins and wargs aside), but that's life sometimes, I guess. (But Gandalf respects this move, which is worth something!) The War of the Five Armies is a bit of an anticlimax after that, which is emphasized by Bilbo being unconscious for a fair chunk of it.

One of my prized possession as a kid was a glass doorknob that I called the Arkenstone.