Production IG is a really well established studio, having been around since the late 80s. Unlike other studios, there's not really a single overriding trait or quality to their works other than that they're
really solid. They're responsible for some fairly major works, such as xxxHolic, Blood+, and Prince of Tennis. I haven't seen any of those though, so I won't be talking about them.
「攻殻絵」 by Tea
Ghost in the Shell is the thing that put Production IG on the map. The 1995 film directed by Mamoru Oshii is one of the most influential anime movies ever. GitS is set in the future, during a time when the line between technology and humanity is blurred. Following that, GitS comprises two more movies and a TV series, Stand Alone Complex, that had two seasons.
「花酒をタンダに」 by たけのこ
In 2007, they adapted the first of a series of fantasy novels, Seirei no Moribito. The show follows an incredibly skilled spearwoman as she is hired to protect a child prince of the imperial family who is under threat of assassination. It's a journey that has a mix of (pretty well choreographed) action and calmer scenes of living and growing.
「平行線をつなげば」by ayu
Eden of the East is an original production about a conspiracy involving twelve randomly selected people who are tasked with saving Japan. The show examines social problems that are fairly unique to Japan, in particular adults in their twenties and NEETs. It aired in 2009 during the noitaminA timeslot and is concluded in two films.
「HEROES」 by にぼし
Sengoku Basara is 2009 show based on a series of video games of the same name. It features a caricaturized Sengoku-era Japan and lots of explosions, both metaphorical and literal. Amazing feats are performed by real Japanese warlords. It's a surprisingly popular show given its origins. A good choice if you're in the mood for ridiculous action and Japanese history.
「期待しちゃっても…」 by しろたか
They ended 2009 off by adapting a popular shoujo manga, Kimi ni Todoke. This one is about a girl whose social awkwardness and resemblance to the girl from the Ring lead her to be ostracized throughout her school life until she catches the attention of a certain guy. The series is all about how she breaks out of her isolation and discovering the joy of friendship.
Obviously, they've worked on a lot more stuff, being around for so long. Most recently, they worked on the film adaptation for Bungaku Shoujo, which was in theatres May 1 this year. I don't exactly anticipate that they'll pick up my favourite adaptations or anything since they don't really have a pattern in what sorts of things they do, but if they happen to land it, I know it's going to be in good hands.