I have to go with Hush. OMWF is lots of fun to watch, and I hum the tunes for days after each time I see it, but Hush is just gripping. Stellar, and the best single episode of a superlative show.
OMWF is a great episode, and both episodes have great revealks in them. But I was actualy creeped out by Hush, the silence is more powerful then the songs.