Mine is Berserk, it's really awesome and immersive. Also, it motivates me to work-out and live my life to the fullest. If you write your favorite manga, please add an explanation why it is your favorite.
If you want me to choose what manga i read most, I much more prefer One Piece Manga because it is such has a good twist for every page. The battles of every character always catching my eyes, all of it has a good combats and powers. It was also fun to read because of every funny moments. I also get touch sometimes by the sad moments of its drama.