i've never used anything but a single chain ring. no chain-guard, no chain catcher, nothing. as long as i keep tabs on my chain-tension (about every 500 miles or so), i never have any problem. and some chain-rings are typical late-model road chain-rings with ramps and cut-down teeth.

last time i lost the chain involved a combination of hammering at the base of a steep a hill, a flimsy frame, and a too loose chain. i know it was too loose, because i put it back on without having to loosen the rear wheel.