I'm currently using Windows Backup on Windows 2003 to backup my data to LTO tape. It actually works quite well but its *very* basic and the scheduling is a bit cumbersome.
I've tried other software in the past and it's either way too complicated for what I need (e.g.: BackupExec) or it doesn't support "spanning" over multiple tapes (yes! I actually tried software which terminated the backup when it got to the end of the tape, rather than asking for the next one).
What does everyone else use? Ideally it should be free, but I know I'm limiting myself when it comes to tape backup software. It needs to run on Windows 2003 and ideally support software and hardware encryption.