At Best Buy:
Maxtor OneTouch III Turbo Edition 1.5TB External FireWire and USB 2.0 Hard Drive - $579.99
This is a "Turbo Edition" supporting RAID0 and RAID1 [you choose RAID level using Maxtor software]. It costs as little as two internal 750 GB SATA drives on sale but it is a well designed, nice looking external enclosure, and it's got USB 2.0, FireWire 400 and two FireWire 800 connectors on the back.
This device is very quiet and, when using RAID0 and FireWire 800, is capable of sustained 80 MB/s transfer rates over the entire 1.5 TB range.