You guys are missing the point. There is nothing more dangerous than two "qualified" pilots up front with ambigous (sp?) duties and responsibilities. Employing the "crew concept" is much more than merely having two jocks in the front seats. One guy up front is adequate as long as EVERYTHING is working well, the weather is playing along with you, and the ATC workload is light or moderate. Change any of the above three items and it doesn't matter how good you are (or think you are), you're going to need help - it doesn't matter whether you're in a Citation, King Air, or Cessna 182.
I agree with the comment about those guys who have "baby sitting" jobs - those who fly with their boss in one of the front seats. I've had a few of those jobs myself over the past 30 years that I've been a pro pilot - they tend to really suck. It takes more than simply having two pilots up front - you have to have predetermined responsibilities and duties and train as a crew. If you have two guys trying to do each other's job confusion will result with a corresponding loss of situational awareness and decrease in safety.
Jetguy