I used a knock off pelican case. I tried one of those tool box things already posted, but didn't like the way it looked. It also felt too fragile. If you can swing it, use a real Pelican case, they're spendy, but built really tough. My box is now water resistant, but no longer water proof. I did seal all the fasteners that go through the box with silicone, but there's really no good way to seal the network port.
http://web.mac.com/barrywoods/Site/The_Box.html