There is nothing wrong taking shots at different types of names. I once bought the name SnoopDoggyBlog.com after seeing it on an expired name list. Wish I still had it. It makes me laugh. I have registered a lot worse names than yours, too.....way worse.
But to me, PrinceWilliamAndKate.com has to be worth zero because if you ran it through the threads here I don't think you would get $10 for it. So, if the most knowledgeable domainers in the world wouldn't register it, or buy it for essentially reg fee, then it has to be worth zero, even if you sell it to somebody for $100 down the road.
Now, I have seen names that nobody would buy here for $10 end up selling for hundreds, and even a few thousand dollars, but I don't think PriceWilliamAndKate.com is the type of name that you can really get lucky on. If all goes perfect you get low XXX in my opinion. That is a low ceiling and it is the type of name that will cost you way more than you get out of it.....in time, money, etc.
That's how I see things, but good luck with it.