I've been here three years and here's my list:
Food -- Peanut butter (I don't like skippy, I like Peter Pan), Kosher salt (I took some of this back with me), Carnation Instant Breakfast, vanilla coffee mate (I read about this in a British book and tried to find some too!)
House stuff -- heating pad. I think you can actually find some of these here now. Measuring cups I brought back with me last time!
Other-- Shoes and Clothes. I am the only non-British person I've ever met who doesn't like British styles and clothes. I've only brought one pair of trousers and one shirt since I've been here.
I saw Kosher Salt in a pretty jar in the Tesco "nice spice" section.
I did bring my US measuring cups and TB/TS with me...
Heating pad - naa get one of these they are a life saver as long as you have a microwave!
I hear you about the shoes - I am practical and most outfits seem to much for me.
There isn't a lot I wish I brought (since I did bring a lot) but If I could smuggle one thing it would be more dill pickle slices and vanilla caramel coffee creamer ;-)
I wish I would have brought another set of sheets (I have 3) but they were for King and
I should have bought a queen size for this bed. It's not common to find high thread count sheets and I am snobby and don't like 200 thread, its like sand paper (sorry).
I did find high thread count sheets in costco and online here but they are expensive.