Although I like the Hunger Games more, I think Harry Potter will be more famous a decade or so from now.
I think the Hunger Games speaks to people in this age, in this societal setting. It will still be relevant like 1984 is still relevant. But I don't think it will capture the imagination of all future audiences.
Harry Potter is more of a timeless fantasy story like the Lord of the Rings. Plus, Harry Potter has more appeal for all ages. So kids in ten or twenty years will still find the story and the world fascinating.