What you need to do is start selling it as soon as possible. That way you can start testing what the market needs. In my case, most clients mostly need a solid

What you need to do is start selling it as soon as possible. That way you can start testing what the market needs. In my case, most clients mostly need a solid Rails box (with MySQL) that will allow them to focus on other important needs. This also applies to Django and Symfony. In terms of OS, the common bits are safe Ubuntu and CentOS installs. Though they do seek support and some hand holding. How do you plan to market?