Technology review have a nice list of uses for the oh so cute Mac Mini. I'll bulletpoint the list here but check the article for a description on each point:

1. As a Portable Depot for Digital Pictures
2. As a Portable Depot for Digital Pictures
3. As s Regional X10 Server
4. As a Christmas Lights Sequencer (give me strength..)
5. As Part of a Home Theater System
6. As a Car Enhancer
7. As a Hardware Firewall for Laptops
8. As a Physical Security System
9. As a Server and/or Gateway
10. As a Component of a Low-Cost Parallel Processing Array
11. As a SCADA system
12. As a Beowulf Cluster
13. As an iPod Feeding Station

I was thinking of using mine simply as a seperate net media center...