I work for a company whose primary business is not software related. Most documentation for using source control is written with a development team writing for commercial or
One repository for your projects is probably sufficient. I like the typical approach that indexes the layout by project (see this section from the O'Reilly Subversion book):
/first-project/trunk
/first-project/branches
/first-project/tags
/another-project/trunk
/another-project/branches
/another-project/tags
/common-stuff/trunk
/common-stuff/branches
/common-stuff/tags
Keep in mind that you can always reorganize the repository later.
Also, for in-house stuff, I prefer FSFS for the data-store, as opposed to Berkeley DB. FSFS is more resilient and the speed of checkouts is not much concern for small teams/projects. You can compare and decide for yourself.
Other standard parts of the recipe include Trac and a minimal Linux server to host the repository on the LAN.