The local rivers i fish are covered on the bottom with leaves and jet-some this time of the year, but I fish mostly a full sinking line. In order to combat this I usually throw my flies with a 1mm foam head. I run about a foot and a half of leader and then the fly. The water is only 5 feet or less so the line normally drags by the bottom. The fly floats up a little and generally keeps it out of the bottom layer of crap.
Smoke 'em if they are Cohiba's.