[acm46]

I think all of these points are valid, but I'd like to add another: being technical substantially increases your credibility among potential employees, VCs, and fellow entrepreneurs. Even if you're not planning to be the back-end systems guy or the rock-star designer once your company scales (and chances are, if you're a founder, you won't be), having coding competency helps you make those hires more easily and will win the respect of your more technical employees. VCs also love it when you're the one who has built the first few prototypes of your site and haven't simply outsourced the work to others.