Not in the UK, not going to watch. I simply do not care if two people I've never met get married.
The Royal Family are useless, but they are also (thankfully) completely irrelevant. They do nothing - so why should I like them or hate them?
Yes, TECHNICALLY the Queen has a lot of power. But in practice, she cannot use that power except in extremely dire circumstances. The Queen realizes that if she actually tried to use her royal powers, the British Public would very swiftly overthrow the monarchy.
So she doesn't do anything. Her family doesn't do anything. They sit in their palaces and play dress up. Occasionally they'll record a TV message or hold some sort of ceremony, but they don't actually DO anything. The queen, and indeed, the ENTIRE ROYAL FAMILY could drop dead tomorrow and it would be relatively easy for the UK government and the UK public to continue on as necessary.
So - to sum up: The Royal Family are useless, harmless, and utterly, UTTERLY irrelevant to 99.99% of UK citizens, and indeed, world citizens. The Royal Family serve no functions that couldn't quickly be transferred to elected officials in the event of their deaths. They are not exceptionally talented, intelligent, beautiful or refined - they did nothing to earn their wealth or power - they merely ride on the accomplishment of their ancestors and the British People.
So why would I care that some Prince, who I've never met, is getting married to some woman I've never met? I don't know these people - and the likelihood is that you don't know them either. They aren't your friends - the image they project on to TV is a carefully sculpted and crafted publicity image fostered by PR people - you're not actually seeing them as they are.
They're little more than celebrities. And I can ignore celebrities.
As long as this William doesn't get in my way, I don't care who he marries or what he does. He could marry a goat for all I care. He could jump off a cliff for all I care. And before you say "Well, he doesn't care about YOU either" - yes, I know he doesn't care about me. I don't expect him to. I don't expect the public to fawn over me either, because I haven't done anything to deserve such adulation.
But, neither has he. Point out ONE THING, ONE SINGLE ACCOMPLISHMENT that merits such attention. Yes, he's a pilot - big woop, lot's of them around. Yes he served in the armed forces - but so have PLENTY of other folks, some of whom were wounded or DIED in the line of duty. I have far more respected for the poorest dead UK soldier, than I would ever have for a ponce who got to where he was via accident of birth!
Any doctor who helps patients is a more worthy person than this Prince. Any conservationist preserving a forest is worth more than this prince. Any charity worker, on any part of the world, is more deserving of respect than this rich boy who doesn't even do anything of worth with the wealth HIS ANCESTORS (not him) earned for him.