ASR in Windows 2003, where to backup?

I’m interested in finding out what people out there do when using the Automated System Restore (ASR) capability on Windows 2003 servers. I’m looking to implement that on our servers here, and I would like to get a feel for how others are doing it. Perhaps doing this to an external hard drive, a shared drive on another server, or just a separate hard drive on that server.

Thank you much.