I know this is probably worth an eBook of its own, but could you very briefly describe your harddisk setup and roughly outline your backup strategy, please.
At the moment I'm using referenced masters on an external (Ubuntu) file server over a Gigabit Network, but would like to switch to an external (Firewire?) drive to increase the I/O speed. Although it has some advantage (backup-automation and such), having master files on a network drive is not ideal, I think. It's also a non HFS file system, but connected to my MacBook Pro using Apple File Protocol.
My library lives on the internal disk of my MacBook Pro. Currently my pictures are backed-up daily/weekly/monthly to an external disk from the Ubuntu Server and I also do upload them offsite using a service called Crashplan (which is fantastic, b.t.w.).
To backup my library I use TimeMachine and do occasional Vault-snapshots to an external USB-disk.
I would love to hear your thoughts and to learn some details about the system you are using. I know you have your main library on an iMac with multiple Firewire drives for your Masters and you do backups (automated? daily?) to a Drobo. Would you be willing to share your setup, please?