Hokuto no Ken was shounen: serialized in Weekly Shounen Jump alongside Dragonball.
I support this as well.I'd like to nominate Zetman for best seinen.
Zetman is about how two heroes came to be, from their early years until... who knows when. It has a captivating plot that resembles that of a book, i.e. mostly slow but steady development, that doesn't leave any detail out. The mood of the story is very diverse, ranging from horror and disgust to joy and happiness, giving off pure human emotion. Finally, it has great and very realistic artwork.
For fans of realism and good, solid plots, this is a must-read.