Queen Elizabeth and her Prince top my list.
After that, it's difficult to rank. If I got to have an actual conversation, I'd love to meet the Earl and Countess of Wessex, because I've always been curious about birth order in royal families - but also, he seems like such a sweet person.
But, to be honest, I'd put Prince William above the Earl of Wessex (and I'd prefer to meet royals with spouses with that spouse, so Kate would have to be up there).
Then Charles and Camilla.
I saw Camilla on the telly last night and she was talking about what she'd fix the Queen for dinner if she were having her over, and what the Queen likes to eat and I thought: she's a woman who might actual dish a little. And, as for Charles, I like his use of English and his interest in the environment - what fun it would be to speak with him.
So maybe Charles and Camilla above William and Kate. So hard to decide.