Not sure if you are still around -your post was old! I'm British and emigrated to Colorado in 2000. I live near Colorado Springs and love it here. The summers are fabulous (shorts and sandals from the end of May to at least October - and sometimes in January as well LOL!). The winters can be cold, and snowy up in the mountains, but you also get clear azure blue skies and sunshine most days in the Winter too. Thunderstorms are common around tea-time in the Summer, and can be violent with large hail - but they don't last for long and then the sky is as blue as it was before - most Coloradians are early risers so that they can take advantage of the day before the storms come in, which can take a bit of getting used to for us lazy Brits LOL! (Think 6am on a Sunday morning and your neighbour has ALREADY mowed his lawn, gone jogging and is halfway through building a gazebo!).
Colorado is generally a very safe area - certainly I feel safer here than I ever did back in England. I feel happy going hiking alone and there is none of the petty theft that you get in England (i.e. the kids can leave their bikes out on the front lawn for days on end, and nothing ever gets taken).
There is a British Shop in Colorado Springs, and probably some in Denver too, where you can get your Cadbury's choccies, Marmite & Branston Pickle from. There are also a few nice Indian restaurants for that Saturday night curry. Jack Quinns is an Irish pub in CS, and there is also The Wayfarers, a British/Irish Pub run by a Scot (!?). There are good Irish & British pubs in Denver too.
The things I miss the most are being so far away from the seaside, and the relative lack of availability of healthy, low fat foods (although the situation is getting better) - no fat free creme fraiche here, and low fat minced beef (<5% fat) has only just appeared at our local supermarket. The range of global foods is fairly limited compared to what we are used to in England - and the price is MUCH higher for many foods (although eating out is so dirt cheap, it often costs me the same amount for ingredients to cook at home as it does for us to eat out - weird!). It can get a bit frustrating trying to cook using British recipes, because there's always some ingredient that you can't find.
Avoid the bread, chocolate and bacon - all are awful. The bacon is about 90% fat and you can't get 'back bacon' here, only streaky (VERY streaky). Buy a bread-making machine
Oh, and remember that 'Whoppers' are NOT the same as Maltesers, even though they seem to be. You will die if you taste them they are so disgusting LOL!
The quality of food in restaurants is excellent compared to in England, and the service is much better too.
Electrical items can be tantalisingly dirt cheap - but we've learned the hard way that you get what you pay for (4 coffee machines, 2 breadmakers, 3 kettles, 3 toasters, 2 food processors & 2 blenders in just 4 years!). If you want it to last more than a few months, or you want it to actually do the job you bought it for, then go for the pricier versions.
Delivery services can be rather slow - and expensive if you live in a rural area - The delivery time on our washing machine and dryer was 2 weeks (eventually hubby had to go and pick it up from the warehouse himself). That situation has improved with some stores recently though too - so check before you buy.
The last thing to be aware of is that it costs MUCH more to fly from America back to England, than it does from England to America. We didn't know this when we moved here, and now cannot afford to go home to visit
And I would recommend renting out your house rather than selling it (the one we sold in England is now worth twice what we sold it for and we are kicking ourselves that we didn't rent it out instead).
You will LOVE the price of petrol (I don't know what these Americans are all complaining about....LOL!).
Best wishes, Lynda