I was surprised no one mentioned this anime yet. Its based on a light novel series. Even though the first season only goes over the very first of six novels its amazingly well done with great characters so far.
Cool! Strangely I only watched it originally because when I went to AX the chrunchyroll booth gave me a free poster and I decided to give it a try and I ended up really liking the story. Each episode is so good it seems like they last 5 minutes.