The British exception
Excellent read I must say, however I think you've kind of overlooked the UK a bit, as it is significantly different from the rest of Europe and from the US.
1. While the metric system is becoming more and more common, and it's pretty much the only measuring system taught in schools these days, in everyday situations (with the exception of temperature) metric is never used. You will never, for example hear anyone give their weight in KG or their height in CM, or distances in anything other than miles. Remembering, of course that all British road signs are still in Imperial measurements. When babies are born their weight is given in pounds and ounces, the list goes on.
2. As for baby showers and bachelor(ette) parties, we have equivalents in the UK. Christenings (Baptisms) are our version of baby showers, of course happening once the baby is born (obviously) and despite the fact that no one really goes to church or is religious these days, everyone seems to still have christenings. This is when the parents will receive gifts from family members and friends and just a general celebration of the birth of a baby. Our version of bachelor(ette) parties are stag do (for men) and hen night (for women), which are always celebrated, often very wildly, just like the US counterpart.
3. Prom nights are pretty much now standard in all schools in the UK (sometimes referred to as a 'Leavers' Do', as it was actually originally a British tradition which fell out of practice many years ago, making a comeback now, most likely because of american popularisation. As for universities (with the exception of Scotland, and to a certain extent Wales and Northern Ireland), they are becoming increasing more like our American counter parts, with maximum tuition being raised from £3,200 to £9,000 next year (2012).
4. As for languages, they bare next to no importance in the UK. I have never seen a non-English TV show on UK television and I think there has been maybe 5 or 6 non-English songs on British charts in the last 20 years. Languages are not compulsory after year 9 in schools (ages 13-14) and they are extremely unpopular subject choices in the UK and are entering into extreme decline. Someone mentioned that Americans and Australians have no need to learn foreign languages, the same is true for Brits, as we don't share land borders with Europe, so there is no influence from other languages. As for the 2 weeks a year Brits flock to Spain, Turkey, Greece etc, almost always you will find that they make no effort to learn the language of the country, because no matter where you go, especially in tourist areas, English is always spoken, so people often feel no need to bother.
5. Although there are technically 3 main parties in the UK, Labour, Conservative and Liberal Democrats, the latter has never even come close to being in power (with the exception of the present Conservative-LibDem coalition, which the conservatives dominate). So a lot of the time, only the first two are considered the main parties with one being centre left (Labour) and one centre right (Conservative), so we do actually have a system similar to the US Republican-Democrats.
6. As for fast food and soft drinks, we are much much much more closely aligned with the US, with our obesity rates being the highest in Europe. Italian and Indian cuisine are extremely popular. However after celebrity chef Jamie Oliver campaigned a couple of years back, all food in every school in the country is now regulated and has to be healthy. For example in my school, after the change you couldn't buy any chocolate bars or fizzy drinks, everything was healthy.
7. Sports, you missed out Rugby, popular in the UK, France and Italy (Six nations Championship)
8. I have to disagree with your text on marriage being less formal or less important and most people in the UK spend a lot of money on their weddings and rent out big venues to showcase it and often going on honeymoons to exotic locations. However you are spot on with dating, it is far more spontaneous here in the UK and Europe.
As for global awareness, British people are no more aware than Americans or Australians. Most people will only know one world president (USA) and most people could not identify even the most widely known countries on a world map and for a lot of people, not even the UK. I think it's really unfair that Americans seem to get the brunt of the 'no outside awareness' criticism, because we're just as bad.
As for media, I would definitely agree that mainland Europe is far more Americanised than the UK . Something I noticed when I was staying with a French family, was the amount of US shows on their main TV channels (TF1), it seemed that CSI (Les Experts) and other US crime orientated shows were on almost every night, at least while I was there. I don't know if this is the case in the rest of Europe, but I'm assuming it is.
In the UK, the opposite is true, on our two main TV channels BBC1 and ITV1, which together account for just under half the audience share, there haven't been any US shows on prime time since the early 90s. US shows used to regularly be up there with domestic shows for ratings, now they come even close to getting the ratings of our home grown shows. CSI is the most watched import and only manages around the 2.5 million mark, compared to the X Factor 12-20 million, Eastenders and Coronation street 10 million etc. However US shows are much more popular with British teens and people in their 20s, most likely because there simply aren't enough shows made for this demographic in the UK, I really don't know why this is the case.
And the British police, I know they seem to have a reputation for being polite, kind and cautious compared to the US, but this really is not true. I don't know whether its a recent development and this is maybe where the confusion comes from but British cops are actually quite aggressive now.
The religion thing is true, in England for example, people get bullied in school for being religious because amongst youths, religiosity is now near zero (with the exception of recent Muslim, Sikh and Hindu immigrants) and in my personal experience I have both never met and do not know anyone who goes to church, with the exception of people of retirement age and even then it's still not massively important. Even amongst immigrants, the importance of religion definitely wanes from one generation to the next, as the children of immigrants gel much better with the secular British society. One thing I noticed talking to Americans is Christian Rock, something I had never even heard of before.
Sash windows are not the most common windows in the UK, nowadays there are virtually none, most of them are double glazed and open outwards (upwards or to the left or right).
You do see full frontal male or female nudity on UK TV after the 9pm watershed and porn magazines in shops but in recent years there have been widespread concerns, especially with parents who want to put a stop to this.