Chobits is a Sienen Manga that was also made into an anime series. Chobits, like CLAMP's famous creation, Card Captor Sakura has also got sweet characters and has not shown any concept of evil. However, it has churned in more in depth emotional depiction of human relationships and has some good amount of philosophy too. The story line is fairly good and also has a good level of suspense that keeps the reader hooked till the end.
I really enjoyed reading the manga, though I haven't seen the anime, I did enjoy the story and the suspense. However, I wouldn't recommend this anime/manga to those who did not like Card Captor Sakura's sweetness and "no evil" concept. The only aggressive character is a female persocon, whose aggression has not been shown to highly exciting levels. In the end it seems like there will be some fighting, but it did disappointed me as there was none.