“Who are Jon Snow’s parents, really?”
This is probably one of the most important mysteries in the series. It’s not a spoiler since Martin hasn’t directly revealed it yet, but the strongest likelihood (so I and many other fans of the books believe) is just as you suspect – Jon Snow has royal heritage.
Specifically, that he is actually the son of Prince Rhaegar (who was the eldest son of the “mad king” Aerys, and also Dany’s oldest brother) and Ned Stark’s sister Lyanna. And so Jon Snow is the personification of “Ice” (Stark – the North) and “Fire” (Targaryen) and all that will (eventually) entail. Maybe not, but I think that’s what the clues in the books make the strongest case for, and what should fit best in the story arc.
I’m with you on how fantastic Tyrion’s monologue was in episode 8 about the beet-smasher, very much including that great line you quoted. Not in the book at all, so this is a case where HBO actually outdid Martin. That whole episode was one of the best so far in the Game of Thrones.
And the “Live Free or Die” Soprano’s episode – definitely one of the best in that supremely excellent series, too.