I had one but took it down because I did't want recruiters or my employer using it against me, and any employer-ready facebook page is going to be pretty dorky.
Even big-name companies are using these sites during the hiring process and to find potential applicants. In fact, I lived with someone who did recruiting for the biggest internet company in the world, and he routinely used Facebook and MySpace to scout for kids graduating from college soon.
So be careful what you put out there, people. On the other hand, you could view it as an opportunity to put yourself out there in a positive light, too.