I had the opportunity to listen to Haruhi's single "Geki Chuu Kashuu" and I must confess the song "God Knows..." is, by far, the best anime insert song I've listened to. I'm even impressed by how different Hirano-san's voice in the song is -- definitely not something I'd expect from her, so she deserves my salutes.
Is it just me, or Mikuru's song (Koi no Mikuru Densetsu) has the catchy tune of the super robot theme (Big Cytron *coughs*) LOL, it even has the disturbingly intriguing sound FX of a woman sighing at the end of it