This is a hard one, because I read two or three books a week.

I was immediately tempted to say Harry Dresden from Jim Butcher's the Dresden Files. It's my favorite series and one of the few sets of books that I own. The same impulse came for Joe Ledger from Jonathan Maberry's series.

The more I thought about it, however, the more I realized these weren't my favorite characters. They grow but in many fundamental ways stay the same as they started: heroes willing to walk into hell without a water bucket if the situation calls for it.

So I thought about characters who grew and become something better.

That being said, I think Waldo Butters, also of the Dresden Files qualifies. I won't give any spoilers but if you read the books, you will get what I mean.

Oh, by the way, read the books.