I was reading the Jackson Fish Market blog/manifesto yesterday on Alex's recommendation and happened on their rule of three post. Basically, like 37Signals, they feel that an optimal founding team comprises one developer, one designer, and one dogsbody :). This is, of course, a very reasonable idea.
It struck me that in practice, if not in equity, every startup works like this. The first developer and the first designer stamp an indelible mark on process and product that tends to be more persistent than the adaptive vagaries of business planning or marketing.
Common stock or not, if you think you don't have technical founders, you do.
And Jackson Fish folks, you're well on your way, now what will be your Basecamp?