This is one of the things we've struggled with the most. We're huge fans of customer development, but also started a company with a vision. Ultimately, I think part of it comes down to your motivations for starting the company and what you hope to accomplish.

[Shameless plug] You can read more about our battles with this exact issue here:

http://mightybrand.com/2010/01/got-customers-part-2-the-one-...