After one episode, AnoHana (Ano Hi Mita Hana no Namae o Boku-tachi wa Mada Shiranai -- "We Still Don't Know the Name of the Flower We Saw That Day") is one of the most promising shows of the season.
Here is a characters/seiyuus page showing images of the six main characters and their seiyuus, with some info about each seiyuu. Click on the link above or on the image to go to the full page.
The male characters have two seiyuus: one for the older person and one for the child. The same seiyuus do both ages for the female characters.
Toyosaki Aki joins Tomatsu Haruka in another example of Sphere members appearing as seiyuus in the same shows. She plays Poppo as a child.
It's also good to hear Hayami Saori doing a version of her ojou-san voice as Tsuruko. Developing some range.
Kayano Ai, who plays Menma, appears to be an up-and-comer, with that super-moe voice. She was Isana in Yumekui Merry, and will play one of the three main characters in the new Last Exile. And that is only one of four roles she is already slated for later this year. I'm still not convinced: the voice she uses here is a little much even for me. But I am getting used to it.