Since you didn't have options for USB2.0/Firewire drives, I responded to the poll only counting my laptop hard drive, which is 40 gigs IDE, almost always between 5-10gigs free. I have two USB2.0 drives, one 60GB and one 80GB, which I use for backups and extra storage. Those each have about 5 gigs free each. (5GB is like a magic number for me....I start to worry if a hard drive gets below that much free space)