As a writer, I wield all the power. I invent the characters, I put them into horrible situations, and most of all, I make sure the girl gets the guy of her dreams. Whatever fantasy I've ever had, I can enact vicariously onto the pages of my books.
So the type of hero I like to write is kind of my fantasy guy. Fantasy, in that no matter how attractive, the real-life versions are not men I would want to marry. I like a sexy bad boy. Even dated one once...which is how I know they are not keepers. But in books, I can mold them, tweak their flaws into journeys, so they keep just enough bad and sexy, while still being a dreamy hero.
What is it about a bad boy? First of all, they are hot. Drop dead hot. The kind of hot you look at and think wow - he'd never look at me in a million years. But then he does..... Second, they are great at sex (having had so much of it). They stretch the usual boundaries and are super exciting. Third, did I mention they stretch the usual boundaries? Bad boys tend to eschew rules in favor of fun (and good sex). Forces the heroine to live outside her box. This, obviously can lead to some terrific plot developments. The whole point of a book is to step outside of the ordinary, the everyday.
Many women imagine that the love of a good woman can tame a bad boy, just enough to put a ring on his finger. Doesn't usually work (note that George Clooney just broke up with his girlfriend of two years after she gave an interview stating that she wanted to be married). But ah, I am the puppet master, and as a writer I can make it work. Very satisfying. A fantasy come true. (Disclaimer - I married quite the opposite, one of the truly best men in the world, a good guy through and through...and I wouldn't have it any other way!)