The depth and mysteriousness of Lain, plus the warmth of Kokoro Toshokan ^_^
It's not just cute girls with wings or dark anime with old atmosphere (it did those very well, to start). What makes this series most interesting is the story, which is very well thought out and nicely paced, but completely fresh from beginning to end.
"Past life, this life, next life" would be an equally good summary for this series... sounds deep, and it really is. You won't be able to guess what will happen the first time through, and there will be lots of things to think about when you are done. You will definitely watch this series more than once!
+ Pioneer / Google