Quick list of some handy font family groups (often called "font stacks") for web design and Drupal theme development. Includes the three groups that come with Adaptivetheme starter theme and an example of how to set the font-family in your CSS.
Sans serif - smaller
"Helvetica Neue", Arial, Helvetica, sans-serif
Sans serif - larger
Verdana, Geneva, Arial, Helvetica, sans-serif
Serif - smaller
Garamond, Perpetua, "Nimbus Roman No9 L", "Times New Roman", serif