I'd love to see the the UK. One of my SOs spent part of his childhood there, and wants me to see where he grew up, and his favorite parts. I'd particularly like to go on a castle-to-castle ride (you ride from castle to castle or inn-to-inn on horses, and they've moved your luggage during the ride, so you sleep in a new spot each night).
I'd also like to visit Japan, especially to see the shrines, and various tropical places, even though I don't care for tropical weather, to go bird-watching (yes I am a geek). I also want to see India.