Vagabond - Really great series, interesting characters with great development, the art is very good too.
Vinland Saga - WHEEEWW LAWD, this is greatness! The art, the character development, the realistic setting, the godlike fight choreography, tense story, memorable cast, I'm not even completely caught up with it and I already consider it a favorite
It's one of my favourites too, have you reached the Farming Arc yet? And if so what do you think of it? Lots of people find it tedious and some even drop the series because of it but IMO it's a really good arc.