Backup Solution Using Hard Drives?

I would like to know if anybody has setup a backup solution using hard drives? We are using ArcserveIT for our backup software. The owner does not want to use tapes for backup so that is not an option here. Also we have around 120 GB of data thatneeds to be backup. I have found 181 gb hard drives by Seagate that can handle our capacity. Any suggest on this I would appreciated it.
Thanks,
Jimmy