Grandpa : Superman isn't brave.
Angus : Did you take your pills this morning?
Grandpa : Heh Heh. You don't understand. He's smart, handsome, even decent. But he's not brave. No, listen to me. Superman is indestructible, and you can't be brave if you're indestructible. It's people like you and your mother. People who are different, and can be crushed and know it. Yet they keep on going out there every time.
I include that little exhange from the excellent movie Angus to make a point. Christopher Reeve proved braver in life than he did on the screen, and that is no small feat when you're arguably the definitve portrayal of a character like Superman. A lot has already been said about him, and a lot more probably will, so I really only want to add one thing.
The list of people I've considered heroes in my life has always been pretty short, but he made it on there twice. Once when I was a little kid for being one of my favorite comic book characters, and again as an adult for persevering through an ordeal that would utterly destroy a lesser person.
I think that's significant.