I'll give my vote to One Piece. Mainly due to Zoro. And Crocodile.
If you're looking for current Shounen battle mangas, I do think Negima, Fairy Tail, Beelzebub and Toriko are better.
The Bleach manga is better than the anime, particularly as you don't have to wade through endless filler episodes, and worse, filler arcs. The infamous filler arcs of Naruto and the jump to Shippuden are what have put me off from watchng it so far.
I think I might have to look into One Piece. As far as I know the manga has a UK release up to the 50something-th volume.
I need more obscure series to get into...and preferably shorter aswell.