Sure it's shiny, ruby red and super lightweight, holds 500GB and connects—with power—via USB 2.0, FireWire 400 or FireWire 800. But the best thing about the newest Iomega eGo is that it can move files faster than (almost) anything I've seen.
The Mercury-On-The-Go from OWC is a somewhat tempting three-way connectible 500GB portable HDD. Component-wise there are no surprises, under the hood is a 2.5" 5400 RPM Hitachi Travelstar 5K500 with an 8MB cache. With Firewire 400/800 and USB 2.0 you get three-way connectivity and bus power.