Finished reading Bokurano about few weeks ago? I'd give it a 9 ~ 9.5 / 10
it's a real epitome of a tragedy, and the stories of each characters are also very sad in a wide range of ways (not saying why though, since that's pretty much a spoiler by then). As expected a sad manga , it has a bittersweet (even a downer for some) ending, although considering Kitoh (the manga-ka), he probably considers it as a 'happy' ending.
Highly recommended for those who wants sadism and sadness, not recommended for the optimistic and/or can't even handle something like Code Geass' ending (was it even that sad????).
Next anime is Zan Sayonara Zetsubou Sensei + Bakemonogatari (SHAFT + Hiroshi Kamiya ftw?)