1. Naruto - The best all round manga I've read. It encompasses every aspects of Shounen manga but still maintains a touch of reality in itself. Philosophically,Idealistically and Realistically it is a perfect balance. Kishimoto is a genius,indeed. The fights are something I can watch over and over again and again. It's something with which I also feel spiritual connection as well like the way it uses every religion mythology,culture,etc. is quite unique in it's perspective. The worldly complex issues and subjects like Love,hate,power,peace,war,loneliness,solitude,happiness,bond,friendship,etc. is portrayed in a brilliant way if anything. Though the lack of female character development is a issue,but then again Kishimoto himself admitted that he don't actually know how to develop a female character in her best,so instead of making cheap effort he rarely give them a spot,and that's what makes him a true writer. All in all it just needs a perfect shounen ending on a really strong note and it's perfection at it's best.
2. GTO aka Great Teacher Onizuka - This,if not the best,is one of the best manga I've read. Comedy,drama,action,slice of life,complex issues and problems of teenage students,it got everything. It got depth,it got everything. I really felt so damn close and related to every problem this manga showed. It was a masterpiece.
3. Fullmetal Alchemist -If you need one word to describe it,it would be Perfect. In the category of shounen that is. It too got everything in it,dark theme,war,peace,hate,love,etc. The complex way the story has been woven was brilliant. You get surprises every here and there. One of the main things I liked about it is the powerlevel. It was constant through out the series. All that got enhanced was skill.
4. 20th Century Boys -Great is a word that pale in comparison to this series. It's absolute thrilling.And if I were to say that "FRIEND" is one of the best mystery character and antagonist ever created,boy I wouldn't be wrong. The story in itself is great. Character development and realism is it's strong point besides Plot,which is again Perfect. All is all,its a great series to look forward. It gives a message that Loneliness can be a cruel thing.
5. Monster - This is a less known series but boy does it deserve to be known! The character Johan Liebert is enough to make anybody love this series as he is one of the BEST antagonist EVER in all fiction I've read/watched IMO. Johan is also one of the most intelligent character in all of the manga and anime I've watched. The main protagonist is also as exciting as the main antagonist. I just loved his travels as he slowly unraveled the mystery of Johan the monster. This series' message was that human lives are all equal and this is represented through the main protagonist Dr. Kenzo Tenma. I loved how realistic this series was too; it felt as if it was all possible which truly made it scary. People say that the ending sucked but I personally liked it. It made us speculate which is always enjoyable. [copied ya,and edited ,lol]
Others are like this,but I don't feel like describing them
6. Rorouni Kenshin
7. Breaker
8. Berserk
9. Shingeki no Kyojin
10. One Piece.
