i would use the one with the washer, not the o-ring. they crack, and are prone to leaking more often than the flat washers. i also noticed that the o-rings tend to get compressed more and i dont feel like it seals as well. i have both and prefer the washers.
Taps down for kegerator rebuild
"Just remember that the real enemy here are those wine drinking pussies."-BierMuncher