backing up two macs

[erda]

I have an older iMac (G4) and a MacBook (Intel Core Duo). I would like to create bootable backups on my firewire external hard drive. Is this possible? I assume I will need to partition the drive, but which format/partition type should I use?
TIA

[dnanian]

Since you're mixing CPUs, you'll want to partition using "Apple Partition Map".