I am just laughing my ass off about this thread, because who would want most of the things you guys are asking for? I don't even want cool whip, skippy peanut butter or velveeta cheese and I live in the US. Try some great stilton cheese and some walkers shortbread and some organic fruit and lovely English bacon. I found so many good foods in London I can't even imagine why you want the overprocessed junk you all are asking for? Sorry to be judgmental, but man, I would give anything to have the kinds of food availale in the UK.
I changed the way I eat a few years before I left the US, and to be honest, I don't miss a lot of the processed stuff. When I did have some (either back in the States or from speciality shops), I found them to be disappointing. However, I do agree with some of the posters who say that it is different when you move away and are away for a while. Sort of like Rachel Ray. I didn't like or watch her show in the States, but when we got cable and her show was on (briefly), I would watch it every day and fight off fits of homesickness. Some of it had to do with her accent and her growing up not too far from where I grew up, but it has to do with how we weave things into our sense of home more than anything I think.
Anyway, I also disagree with you on British bacon. That stuff is foul. Sorry, I've ordered it from some of the best organic butchers in this country, and it either tastes of the pig or of fake smoke flavour. Bleh. I've only had back bacon a few times where it was decent, and it was a pure premium from Waitrose. Most British streaky bacon is the same way. I'd rather spend my money on OM imported bacon or something from the continent. Mr A says the same thing now, and he used to rave about British bacon. He thinks they changed something about it, probably in reaction to health concerns.
Also, there are a couple things I think the British do better produce-wise, but it's not like there is a homogeneous "American supermarket" which only sells pale watery tomatoes and iceberg lettuce. Maybe I was lucky. The earliest place I remember living had pretty crap produce from the shop, but we lived in farm country. Most people grew their own and stored them or bought from farmer's markets. Now, it's got a monster supermarket with a produce section you could fit my entire first British supermarket in. A lot of it is imported and probably wasted, but you could get a lot more than you can here. Then I never lived far from a Farmer's Market or greengrocer's in NYC. Western NY had the amazing and awesome Wegman's, and I was a member of a local co-op, not to mention farmer's markets. And organic vegetable box schemes are becoming common in the US schemes as well.
I don't find it really that much easier to get really good veg here, but I do think that it's easier to get common veg that is of good quality if you're careful where you shop (if that makes sense).
I do agree with you on Stilton. I can't believe it's not more popular there, especially with blue cheese fans.
What I do miss isn't very good for me. I really miss all the weird and wonderful diet soda flavours. It doesn't mean that I stay up at night pining for them, but I do swing by Partridge's on occasion to pick up some diet A&W creme soda or root beer.