I love whiteboards.
One of the first things I do on any project is get lots of whiteboards installed for impromptu design and troubleshooting sessions.
But they're damn expensive.
On the last project though - a colleague introduced me to shower boards and i'll never go back. The coating on them makes them usable as a dry-erase board and you can pick one up for $15 instead of $500. Check out this happy guy.
3M have also started selling a sticky note version of a whiteboard that can be a less permanent fixture.
Glass walls and Windows are also great.
