Anime recommendation for foreign people 2011 Spring (2nd)

This is the best of this season.

あの日見た花の名前を僕たちはまだ知らない
(We still do not know the name of the flower we saw these days.)
http://www.anohana.jp/
http://en.wikipedia.org/wiki/Ano_Hi_Mita_Hana_no_Namae_o_Bokutachi_wa_Mada_Shiranai

5 people (3 boys and 2 girls) were best friends in childhood.
However, because of an accident, a girl in the group died.
After a few years, the main character, Jintan, suddenly can see and talk with the girl (ghost?),
and she asks Jintan to grant her request (the request is not known even by the girl herself).
Then, Jintan tries to grant her unknown wish.

This is a tragedy, but not only a sad story.
The characters tries to get over the tragedy.