My ideal founding team would have three members: a frontend engineer/designer, a backend engineer, and a business/marketing person. I think this is basically what Seth was saying, and I've also heard the RescueTime founders say that this is a great combination (it's what they have).
I wouldn't really want to go without the business person entirely, simply because somebody has to hold the entire product vision in their head, and the engineers usually have plenty to think about anyway. The tension between "C'mon guys, we can make this better" and "Okay, let's dive in and make this better" seems to be necessary for great creative works. That was really Steve Jobs' role in Apple - as I understand it, he did basically none of the coding. It also helps to have someone take care of all the interruption-driven tasks of running a company - following up on leads, talking to the press, drumming up excitement, getting feedback from potential customers, etc.