Another stocking lover here, for adults not just the kids.
I try to limit the cost (it can so easily rack up) and tend to focus on small relatively useful items.
For kids, things like - magic washcloth, toothbrush (character one rather than usual boring ones), hair clips, small lego figure, pants, crayons/pencils, cbeebies magazine or similar, choc coins, torch, notepad, bookmark, small toy.
Adults - for DH i usually put things like small chocs, nice chutney/small foodie items, camera magazine, socks, pants, nail file (he always nicks mine and hides them), post-its with picture on, small computer item e.g. usb-hub, earphones, etc.
Your DH should definitely do your stocking (you can't do your own!!), you can always give him guidelines - food, undies, toiletries, magazine, nail varnish, DVD etc.