Currently, my favorite is Touch Me. It's just so beautiful!
Close seconds are Mama Who Bore Me (both) and I Don't Do Sadness.
I really like Purple Summer, too, which surprised me because I didn't really like the clips I heard of it. About Purple Summer, though, I haven't seen the show (although I know the plot, including all the really major spoilers) and I was just wondering if anyone could explain to me the basic "meaning" of the song? I kind of get it, but I don't want to go applying all sorts of symbolism that doesn't belong.
"I mean, how many of us could honestly say that at one time or another he hasn't set fire to some great public building?"