Great topic! Oh, if I had it to do over again., I'd make smarter choices. I can't top most of the great advice already given, but I'd choose: a sentimental family photo (unframed), tiny amount of key jewellery pieces, fav jeans and minimal clothing/shoes (really had no trouble with UK clothing, except jeans and shoes due to odd sizes), Zycam, Neosporin, maybe taco and ranch seasoning packets, USA measuring spoons and cup for any USA recipes, laptop/devices. These are my priorities, and whatever else fits that you need and can't readily get in UK. Most of what I thought was not replaceable (certain brands of toiletries, and loads of other items) have long since been replaced. Maybe pack or securely ship key documents needed for immigration and/or tax / banking purposes. We don't have children or pets, so unsure on that front!