Oh man, I come across something at least once a week that I say, I should make a list, so next time I visit (or someone comes here) I can get it in the States. These are just some of the things I have 'supplied' by my mom or visitors on a regular basis:
+Ziploc bags (in every size!) -- I have learned to use less of these, once I bought/brought over the next item...
+Rubbermain/tupperware/generic plastic containers in various sizes. Now I import them for my mother-in-law as well
+M&Ms. For some reason, the ones here just aren't the same.
+Benedryl, for hubby's allergies. Way too expensive here.
+On the same note, we buy huge bottles of ibuprofren as well.
+Non-sticks pots & pans. My husband is just amazed at the Circulon pots I got in the States, and they're so much cheaper there too.
+Non-stick muffin pans, baking sheets, etc. Of course, I had to leave tons home cause they wouldn't fit in my oven, but the rest are very useful (can i just emphasize again that certain things are just so much cheaper from the US!)
+marshmallows. Crazy, huh? The stuff they call marshmallows here are coated with candy stuff and just don't taste right!
+deoderant. Oh yes, there's a reason this was listed on so many other people's lists too. Ugh.
+Dial soap. Sensitive skin + unknown soap brands = paranoia.
+Contact lens solution. This is because I'm very sensitive and seem to have a problem with the kind I get here, even though the brands are the same (but the price isn't!)
+Until recently, I was getting my birth control pills shipped monthly from my mom. Then I was off my private insurance in the US, and I asked my doctor for a year's worth precription. Since I was paying for it on my own, the drug store had no problem with doing it. Of course, it is costly doing a whole lot at once, so I am looking forward to figure out the health care here (yes, something I should have done already!) so I can get my prescriptions here.
+I used to bring over 'feminine care products', until I found Tampax here, and adjusted to the other brands of things for my other needs. I decided one day to just deal with the UK varieties.
+Microwave popcorn. It's here, but it's costly.
+Plus-size clothing. Come on, Evans is usually a joke with their styles, and the only option here.
I should mention that I was spoiled with a warehouse grocery store membership while in the states, and got used to buying in bulk anyway, so my main problem now is shipping all the stuff we need. We usually bring one empty suitcase with us to fill with purchases. It's not just me -- my husband is just as eager to buy the goods cheaper and easier. Yes, I still haven't figured out which stores to buy things in here. But I'm pretty sure that much of my list is not available at reasonable prices in the UK. OK, now I sound like I'm obsessed with money. But it does bear consideration, especially since we travel back and forth, or have people over from the US fairly often (at least twice a year currently).
The next list I suggest is one of the things that we bring to the States for people who have become addicted to the British stuff. For example, one of my friends requests HobNobs all the time, my brother demands DVDs he can't get back home, and I now must have my own supply of Typhoo teabags when I'm visiting 'home'.