Tie 'em, use 'em, and love 'em! Although I'm partial to the Peacock
Bugger (substituting peacock herl for the chenille body), same idea.
As one poster eluded to already, although "classified" as a streamer, I think they do a much better job of imitating large nymphs with articulated bodies (hellgrammites, big stoneflies, etc.). I fish them across and downstream, constantly mending the line. A lot of strikes come as the fly reaches the end of the arc swing and is "dangling" in the current almost directly downstream of me.
One item of note, try to keep your fly rod at a 90* angle to the line during the drift. Sometimes they really wallop these Buggers and if your rod is straight on to the fish and the line is tight, they will pop your tippet.
EDIT: Just saw nick k's post (#11)... so count me in as seconding
a vote of confidence in the Peacock Bugger!