@msolga,
Where oh where to begin?
For a start they are a living thread right back to the ancients of this land, a direct (maybe in a slightly round about way on occasion) link back to the Normans and beyond.
Names, tribes, terminology and events that most people here know of, such as, in no particular order:
Boadicea (Boudicca of the Iceni), King Offa (of Offa's dyke fame), Cnut (Canute), Alfred The Great, William The Bastard (Conqueror), Richard the Lionheart, The Plantagenets, Henry V, Edward Longshanks, the Princes in the Tower, The War of the Roses, The Tudors, the break from the church of Rome (massive event in its time), Bloody Mary, The Virgin Queen, Virginia USA, Sir Francis Drake, The Armada, the game of bowls, Lady Jane Grey, The Stuarts, the beheading of Charles I, the civil war, Oliver Cromwell, the House of Hanover, the colonisation and eventual loss of America, the madness of King George, Queen Victoria, and the numerous places around the world named after her, Prince Albert and his passionate patronage of the Sciences and fledgling industry, the great exhibition, the spreading of the industrial revolution around the empire and eventually around the entire world, The Saxe Coburgs, The Windsors, the abdication, George VI and his wife, the Queen Mother, WWI and WW2 and the need for a serious rallying point, our present Queen, and that is just a snapshot.
A deep and undying Rallying point for the nation when our backs are against the wall, is how I would sum it up.
"I know I have the weak and feeble body of a woman, but I have the heart and stomach of a King" - Elizabeth the First, rallying the troops at Tilbury on the eve of the Armada, 1588.
" I see you stand like greyhounds in the slips, Straining upon the start. The game's afoot. Follow your spirit, and upon this charge Cry 'God for Harry, England, and Saint George!' - Shakespeare, readily acknowledging Harry (Henry V) as a focal rallying point in the 1400's.
Into more modern times and Britain's "darkest hour", 1940.
(From Wikipedia) -" The Darkest Hour is a phrase coined by British prime minister Winston Churchill to describe the period of World War II between the fall of France in 1940 and the Nazi invasion of Russia in 1941, when the British Commonwealth stood alone against Nazi Germany and the Axis Powers in Europe. It is particularly used for the time when the United Kingdom was under direct threat of invasion; following the evacuation of the British Army from Dunkirk and prior to victory in the Battle of Britain. The darkest moment is usually considered to have been 10 May 1941, when over 1,500 civilians died in Luftwaffe bombing raids on London alone"
Two things here. One, the commonwealth was fighting, and not the Brits alone.
To quite a few of those brave Commonwealth soldiers (not all, admittedly, but certainly the majority), they were rallying around the same figurehead that the British soldiers were fighting for. Britain as the mother country of the Commonwealth, with the King at it's head .
People must remember that, despite how Hollywood may beg to re-educate the masses, the Americans were nowhere to be seen at that time.
The rest of Europe had fallen.
Without the help of those many brave soldiers, sailors and airmen from the Commonwealth, this country would no doubt have been either blockaded into starvation and eventual surrender, or invaded and beaten comprehensively. Without that aid in those early days, Hitler would have very probably been able to concentrate more of his forces in our direction. The fact that he couldn't, meant that he left Britain free to become a staging post for the US when they had finally been cajoled into sending actual armies, as opposed to lend lease goods and machinery, of which all had to be paid for at a later date (I believe that the British Government finally finished paying for it in about 2005?)
You could say that the forerunner of Halliburton was alive and kicking even in those days.
Tom Hanks and Spielberg be buggered, the majority of troops landing on D-Day were British and Commonwealth, and the main reason the Commonwealth lads were there was because of their ties to this Island, and the reason that this miniscule Island was (note the word "was") sufficiently influential to create a Commonwealth in the first place was because of our unity around the flag and the propensity that they all had (note "had") to rally round our King or Queen in time of dire need. Thank god they did.
Modern times (post war) may have changed the viewpoint of many Commonwealth or ex Commonwealth member states and their peoples, especially after the way in which Britain cast them aside when it joined the European Union, but the fact is that they wouldn't probably exist as they do, if it were not for Brits going there and, lets face it, taking the place over in the first place.
The same goes for the USA.
And the Brits wouldn't have been sufficiently united and/or driven to spread themselves around the world without the one common rallying point, that was duty to their country, the monarchy being its all powerful figurehead.
Australia, without all this swashbuckling and conquest, would probably be speaking Dutch (maybe).
India would be without a common language (probably).
France (as with most of Europe) might be speaking German, but would more likely be speaking Russian.
The USA would have no influence in Europe at all, as that would be where the post war Iron Curtain commenced, and they would probably be speaking and acting French anyway, so they would probably just shrug their shoulders at such a situation.
Getting back to the subject in hand, the idea of Monarchy flows through the blood of every Brit, however much the supposedly anti royals bluster and rage against them. Our history has made us who we are, and our history is irrevocably entwined with Monarchy.
Show me one Brit who is dead against them, and I'll show you ten Brits (and hundreds more non Brits from other shores) who will fill with pride on the day of the wedding, and no doubt shed a tear as they watch it all on TV.
I could go on....
Their function in 2010? To keep our communal feeling of history, and I'm not just talking about 200 or 300 years of the stuff here, but thousands, alive and well.
What do Yanks want to see first when they come here ?
The same things that most of us pass by every day of the week, but totallt take for granted until something like a Royal wedding comes along.
Living history. It's everywhere you look over here, if you have a mind to.