Pretty much anything from Marks & Spencer foodhall is a winner--tins of biscuits, teacakes, tarts, jam rolls.
For my friends' kids, I bring back little HappyLand figures from ELC. They love them!
I'm kinda bummed that after the Olympics, there won't be any fun tea towel purchasing events. Royal Wedding, Jubilee and Olympic tea towels were my primary gifts over the past 2 years.