We moved into some new administrative offices here at American Public University System in Manassas, Virginia (Washington DC metro region). About 40 of us had been staring at blank (off-white) walls and then a few months ago we decided to invite employees to submit photos they had taken over the years. A small group of staff sorted through the submissions and picked two dozen photos to be enlarged, matted and framed. The end result is fantastic! While I might be biased (a few of my photos were chosen, and now employees are calling it the Dan Soschin art gallery), I will say it was an inexpensive and diversely captivating way of decorating our office. It also has a bit of an academic element, which is extremely appropriate given that we are a university.
During this project, which was incorporated into our other buildings as well, we happen to come across this article which is extremely relevant to the project.
Have you thought about updating the decor at your office? Maybe employee art is the way to go. You might be surprised at how talented some of your staff can be outside the office.