Mac mini with Snow Leopard Server owners can add an unlimited number of Mac and PC users without per-user licensing fees. The Mac mini's back side ports include Gigabit Ethernet, USB 2.0 (four ports), HDMI, FireWire 800, and audio in/out. There's also an SD card slot and a Mini DisplayPort.
The Mac mini seems well equipped for office life. It may achieve greater success as a small business server than as a living room media center, particularly if the next incarnation of Apple TV is a hit.