>I read Superman for years, but never liked the fact that he was too hard to kill. They had to keep inventing new types of kryptonite to get him.

Come on now. If they (superheroes) were easy to kill they wouldn't be "Super".
I was really into comic books back in the 70's and early 80's. I wish that I wouldn't have unloaded the collection to pay off student loans after college. Had like 3,500 books total. All bagged and in great condition. Got $1,500 at the time but would have been worth much more now.
Same problem with Baseball cards.

Live and learn.
Maynard