well my list will be abit different i think than most, anyways here it is, no particualy order....
1. Vagabond - not sure if its a shounen though however imo its one of the best mangas ever written.
2. vinland saga - relatively unknown i think, which is a darn shame, because i will almost go as far as to say its the best manga ive ever read, only shame is that theres only 6 volumes out atm, drawing style is a bit like beserk exept not as sketchy.
3. hajime no ippo - had to be there, im a boxer so ofc i love a boxing manga, but even if it wasent about boxing it'l still be there, just out of its comical value (if thats a phrase?) who dont laugh of takamura and aokis fights! simply love it
4. one piece - classic manga, funny good storie loveable characters and everything, clearly one of the best shounen in new time.
5. slam dunk - well u all prob know it, great manga loveable main person, i have a weakness for dillenquent mangas, and this is one of the best, together with GTO imo.
theres alot more that i like, like bleach, naruto, prince of tennis, etc. just took the first 5 that came to my mind to list....
well this is my first post so ill also introduce my self hello there mathias is the name from little ol denmark, i have a manga collection thats about 40gb big i think or there about so ive read a few i love to discuss manga, and talk about it... anyways a final not, if u havent read vinland saga, read it! its awesome beyoung believe