I keep mine in a zippered portfolio thing, called a ManFolio.

http://www.countycomm.com/manfo.html

It was not specifically made with idea to carry a netbook or similar, but the eDGe fits just fine and has some extra room for a few other items and papers. I removed the little extra pockets with the rings from it so it would lay flatter. Part of why I like it is it hides what I'm carrying, making it look more like just a paper holder, and thus a slightly less tempting target for theft. And being a fan of E!'s The Soup, can't resist when people ask me about it:
"Whatcha got there?"
"ManFolio"