My DD loved her presents from my DS when she first came to visit him- he bought her an umbrella, a jigsaw and some pencil crayons- she was 2.6 and these were all things she really wanted then. Didn't stop her playing up not shortly afterwards, and every subsequent visit, but guess she may have been even worse without the presents.
Not bought any presents for DD and DS yet from the baby, but guess a few chocolate treats would probably endear him more to them than any other gift lol.