ExtremeFitness.Com rocks! Okay, well, I'm biased; not sure what a good header does for you, but having members who know what they are talking about is important.
Yeah ExtremeFitness has a very good header and it really stands out, having a good header doesn't really do much for you except for those who go to a forum and have no idea what it's about unless they see some sort of graphics then they know right off the bat, I'm one of those type of people.