I'm still waiting for mine - paid for it, but in the mean time, let's post ideas of what to do with it.
1) Media / Internet TV box.
2) Networked projector
For #2 I would run VNC server and VNC client (or other suitable software) on it and connect it physically to a ceiling mounted projector, allowing users in our office to connect to the Pi wirelessly over VNC from their lappies and run another VNC session from the Pi to their own machine for PPT's etc. I'm sure there's a better way, but I like the thought.
Any ideas of what works on the Pi (media center wise?)