I use the cheap plastic click-on rails from Sears. I like them because they are cheap, I can mix and match squaredrive sizes on one rail to keep types of bits and sockets together, and they are a LOT more durable than I expected. They stick up out of one end of the beat up duffel bag I haul my junkyard tools in, and have been snagging on random stuff since April or so. Not a single one has broken yet. I also sling them under jeeps and toss them into the bed of my MJ with very little care and fully expected them to break with this kind of treatment but they are still in one piece. I still haven't had a socket fall off a strip, either.
EDIT:
http://www.sears.com/shc/s/p_10153_12605_00941829000P?prdNo=14&blockNo=14&blockType=G14 is a 3 piece set of em, a rail for 1/4", a rail for 3/8", and a rail for 1/2". I bought them in-store though, easier to find everything since it's all together on the rack.