This really isn't the thread for that discussion, a discussion so old...
well, anyway, my 5 cents - the most distinctive differences between USA and UK:
* Religion (massive differences here - Anglican state church versus a heck load of creeds in a system of rather strict separation of state and church - although some right-wing christians tried to change that very American core value in the younger past, a core value that separated the USA from England and most European cultures very very much, a core value that was developped by English culture, but could not be established in England till this day - it had to be established elsewhere, and that's all the US is or was about; and today? England is one of the nations with the most atheists or humanists in the world, wheras the US still is, especially in the Bible Belt, a God-fearing and religiously loaded society - no way that a US American president could be an atheist - in the UK it is certainly imaginable)
* Immigration & Frontier (be it Afro-American ex-slaves or German Forty-Eighters or Chinese railway construction workers, gold-diggers, whatever - England only became somewhat multicultural in the younger past after WWII, you could say England became influenced by American culture in the last 100 years than the opposite way)
* War Spirit, Traditions (UK still likes to play chess but well, we all know: Britannia is far from being a world power anymore. And UK citizens have become quite pacifist like the rest of European societies after the destructions of WWII - destructions the US never had seen on her own soil - and after the process of de-colonization. The US became a super power, somewhat imperialistic and reckless in the Cold War (Vietnam, Nicaragua, ...) and till this day Americans feature a much more militaristic approach to politics, and there is much more proudness about military tradition, supporting the troops, because so many Americans are serving as soldiers, everybody knows someone who is fighting somewhere abroad or has lost a father or son - there's a distinctive difference in military culture opposed to the UK; or take other things like the right to bear arms - for British people it's pure cowboy and child-killing madness, for Americans it is part of their tradition - not all Americans want that tradition continued, but I hope you know what I mean: there is a distinctive American culture that has developped in the last 300 years and there are strong differences between the US and Europe, in many ways modern England has more in common with France, the Netherlands, Denmark or Germany than the US - England today is the bridge betwen US and EU, influenced by both and influencing both, but in no way can USA and England be put into the same bag)