Ya know? Sam and Dean Winchester might have been in Kripke's brain, but I'm not at all convinced that I'd like them as well if they were played by anyone other than Jensen and Jared. Sure, Kripke created them, but J&J give them life.

I can't say for certain, since I have nothing to compare it to, but I'm pretty sure it's J&J's Sam and Dean that I'm in love with, rather than Kripke's characters alone.