I went with a Zero Chroma Vario plus an invisible shield.  They add very little weight, yet protect it pretty well.  
When traveling with it, I flip the iPad over and the screen is protected. I also slip it into a cheap $5 neoprene netbook sleeve for going through security at checkpoints so it does not stand out as an iPad.
				
			When traveling with it, I flip the iPad over and the screen is protected. I also slip it into a cheap $5 neoprene netbook sleeve for going through security at checkpoints so it does not stand out as an iPad.