Introduction: Data Safe
The fastest and possible most secure back-up drive. Take one safe, one UPS, a gigabit NAS enclosure with a RAID 1 configuration and there you have it.
Fast with minimum security risk, protected in case of fire and instantly accessible. I've got an uptime of 136 days and counting with no overheating and gigabit rates, with all that your data can just live safely on the network.
Another option if backing up over the net doesn't fit your needs.