Greg,
There are values to having a partitioning schema. Typically, these are:
- Security: nodev, nosuid, read-only, or other filesystem mounting options
- Damage containment: filesystem problems, such as filesystem full or filesystem corrupt -- might allow unaffected applications to continue.
Most new-to-Unix-like-systems admins spend a great deal of time attempting to perfect their filesystem configurations. This is usually a waste of time; every situation is unique to the OS and its particular usage. As ocicat mentioned, I recommend new admins start with a single filesystem until their configurations stabilize. I even recommend that for experienced admins who are provisioning new systems.
I have systems with many partitions, but I also have a personal laptop with a single large partition, less some swap space. On that laptop, the benefits of partitioning are not outweighed by the flexibility I require for my varying application usage on that platform.