Here are some Raspberry Pi resources:
- Printable PDF of the casing (link)
As Raspberry Pi is a board with processor, RAM, and connectors, the handy additions include:
- SD card,
- HDMI cable or HDMI-DVI adapter,
- USB self-powered hub to connecto the following:
- mouse and keyboard,
- Wi-Fi adapter,
- external self-powered disk drive or USB stick.
Other possible additions could be (all USB): 3G dongle.