Lots of great ideas here. We'll also be including a hat/glove/scalf set and new wellies. I've also just got him a small hand painted treasure chest that he can stash his "junk treasures" in as he loves that sort of thing. We normally also do new colouring pens / pencils and a bubblegum box filled with every flavour of chewing gum and bubble gum you can imagine.
I wish they would make a chocolate satsuma! Like a chocolate orange but satsuma flavour and size/shape, and not in a box just in its peel coloured wrapping, so it has the same visual effect as a real one.