In order:
1. Monster. A perfect, well written psychological thriller. Spans 18 volumes long, and oh so good! Definately my favorite manga and anime. Urasawa Naoki is the best mangaka ever!
2. Happy! I am beginning to enjoy Urasawa Naoki's other work. Synopsis:
I love how urasawa always uses ordinary people who have to overcome their situations.One day the Yakuza comes knocking on the door of the orphaned Umino siblings. The oldest brother has gone into hiding after acquiring a huge debt. Afraid for her brother, Miyuki agrees to take responsibility for the loan. The yakuza wants her to become a ho, Miyuki wants to be a tennis pro. Turns out she used to be a very promising player before her parents died. However, becoming a pro is difficult when friends are few and everybody else conspires to make Miyuki's life hell.
3. Azumanga Daioh! Who DOESN'T love it?
4. 20th Century Boys. It is just sheer amazement. Also by Urasawa Naoki. Another good psychological thriller. Less attached to reality though. But nonetheless amazing.
5. Tie between Yotsubato and Death Note. Both are good, totally different genres. Yotsubato being wacky, comical, and lighthearted like Azumanga Daioh. Death Note being an awesome logical thriller.