I'm expecting everyone to say Special but..
There's been like 30 or so manga, eh? At least that's what I counted, probably including movie adaptations..
So which is your favorite?
Mine is Golden Boys. I can go on for posts about how awesome it is and how it shouldn't have "ended" but.. Yea.
It just seems like the perfect manga for the series, and it isn't even super close to the games.