Recently, Omega introduced external hard drives that are compatible with Mac. The best among the batch is the 1.5TB UltraMax Pro Desktop, it is equipped with two SATA-II drives in a meshed enclosure, which gives it a Mac Pro look. You can set these drives in RAID 0, 1 or JBOD configurations.
This version features two FireWire 800 ports, one FireWire 400 port, and a USB 2.0 connector. It also give you the option to choose from eSATA and USB 2.0 interfaces. The eSATA features speed of up to 3Gbps.
You can UltraMax Pro Desktop for $600 and you need a Mac OS X 10.3 to run it. The other models are Iomega's MiniMax line and eGo portable drives.