My First Ghost by Maggie Miller & Michael Leviton, illustrated by Stephanie Buscema is a silly and hilarious addition to the picture book collection. I'm not putting it with the Halloween books, but it would be great to use around Halloween.
Be careful, this book is haunted, it boasts! The illustrator boasts that she creates with pencil and paint on paper to carry on tradition. And her artwork, to me, is reminiscent of the older Disney and Little Golden Books illustration. Take a look at Stephanie Buscema's Blog.
The story is very convincing that a ghost is better than a sister or brother or a pet and you don't have to worry about feeding them!