How Do You Manage a Product Based on Linux?

Ryan writes "Following my advice, my company has decided to base it's new appliance on Linux. So far, it's worked out great. Linux gave us a huge jumpstart on development because of it's open nature and the information we've garnered from public mailing lists. We've added software, modified startup files, and have built our own kernel. Now the question is: How do you manage it all? Do you put it all in CVS or Subversion? Do you use the distro's packaging system (we're using Debian)? What does your build system look like?"