Isn't it weird that Earth's champion is an alien while it's chief villain is an Earthling?
I've always enjoyed that fact.
I've always found it interesting the difference between Lex's upbringing and Clark's --did Lex have bad parents compared to Clark to end up as the "bad" superman? By all accounts they were very thoughful parents and raised at least one superhero --Lena Thorul.
Not by all accounts, actually. Luthor had abusive parents in both
Luthor's Gift and
The Adventures of Superboy. As for established canon, I never really got the impression that they were particularly good parents. Then again, we never really learned much about them.
In any case, I think that Lex has only himself to blame for being a super-villain. In the end, humans have the ultimate choice and are fully responsible for their own actions. Of course, that also means that his career as a super-villain isn't a fixed one--at any time he could decide to give it up. He almost did at one point.