The box will contain 1 Raspberry Pi board.
You will need a micro-usb power adapter, KB, mouse, SD card, and HDMI cable.
Don"t forget the USB hub if you want to use keyboard and mouse. I"m thinking an ideal solution is powered USB hub.
The model B (which the first batch consists of) has two USB ports, so no hub needed for just keyboard and mouse. Another possibility that will save a port without a separate hub would be a keyboard with its own usb port for the mouse; yet another would be what I"m trying, which is a wireless keyboard & mouse combination with a single receiver dongle. So long as the dongle presents itself to the board as a standard keyboard/mouse there shouldn"t be any driver issues with Linux. Mine arrived today, and didn"t contain any any driver CD, so I"m confident it"ll be fine.