More responsibility. I've taken it as a given that it's part of career advancement and I take on progressively more and more responsibility and authority to earn more money. There's nothing wrong with that, I'm just jealous some people can code and code and code and still have a successful career.
Well, it is true that you can't really dodge responsibility if you want career advancement. That being said, if you love to code and you want to limit the non-coding portion of your job, your best bet is to really hone your skills as a high performance systems-level engineer. That track probably offers the most advancement potential in terms of "just coding".
Been working for me for years...