Oh, you guys... SiD, you may stay. I like you. Also, that's a lovely photo of your barn cat. I encourage to soak up the sense of space that your picture gives... I don't know how you can do that, but try to soak it up while you can. And
eat all the noms! Pack whatever you have room for that won't spoil or spill into your suitcase. Favourite spice mixes, sauce powders, etc. Even things that are sold over here and look familiar won't taste the same (tinned veg in the US all have salt in them unless you get the tins marked "no salt added", whereas here, they are all unsalted... it's a noticeable difference! But at least that one can be fixed by adding salt. Other differences are not so easy to fix.) Oh. Tinned pasta. I won't lie, back in the states, I still loved to open a can of Spaghettios with "meat"balls and have that for lunch. Over here, there is not a single tinned pasta that is even remotely enjoyable. I'm not sure how they fail so badly, but they do. So bring your favourite, if you have one.
To answer your specific question, I think about 95% of us miss Mexican food. Having said that, many of us are making our own, and there seems to be brewing interest among the British for Mexican food, so it's easier to get ingredients, Taco Bell has about a dozen restaurants around the UK (admittedly, that's "fast food", not "Mexican food", but it's Mexican inspired, so it'll have to do... plus, it's tasty).
The British (or just my husband?) don't know what a Chicago deep dish pie is. If that's your preferred "pizza" style, you'll need to learn to bake it. I like all styles, so I get my pizza fix often. But occasionally I think about a good Chicago pie and I get all drooly. When I have an oven*, I'm going to introduce my husband to the goodness that it is. He'll hate it, of course. (Then again, he was really happy with pot roast when I showed him what that is... and he was practically a snob about proper rare roast beef before that.)
* We're at the planning stages of a never-beginning-so-how-can-it-possibly-end? kitchen rebuild, and we don't have a cooker. We've been living this way for 19 months, now. I've pretty much just come to terms with the fact that I'll be cooking on a camp stove in my utility room for the rest of my life.
Also, actual photo of me breaking down boxes for recycling:
