Much like everyone, I would say 10,
Kokoro Musubi worth the CD itself.
That said, I really like N° 2 as well,
Gekka no Duelist (nope, not yugioh thing XD). At first it doesn't sound higurashi at all, as it sounds like something from an action/adventure/heroic fantaisy song, with the usual sword wielding hero, until the image of Keiichi with his bat popped in my mind
Common wish (3) started as bland, but quickly pulled insanely great instrumental spike, while Yuzuki-san was chanting nicely, just as usual.
The rest is fine, though the only true disappointement was probably integral integral (anNina was fine, but the music wasn't...).