Last year I reviewed several of my favorite Halloween books. If you've already read through those (and these, and this one, too), here's a quick list of superpicks for even more slightly-spooky-times enjoyment:
Bone Soup is silly (like Stone Soup, except with toenail clippings and mouse droppings... EWW!)
Bats on the Beach isn't really Halloweenish, but it celebrates the cuteness of bats.
Runaway Mummy is yet another clever parody (for those Runaway Bunny fans.)
Moonlight the Halloween Cat is cozy and sweet (no scary stuff or creepsiness at all, just nocturnal animal buddies and friendly scarecrows with comfy laps.)
Skelly the Skeleton Girl has awesome illustrations and just tidbits of words. And the bone theme works well tying in with lots of naturey topics.