Why do you limit this to 5, why you do this to me? I'm going to completely disregard it because it's too hard and think of the ones that come to mind for now in particular order.
- Dragon Ball series: Got me into anime which then got me into manga. The most influential series. Thank you for getting me into anime Toriyama.
- Yu Yu Hakusho: Absolutely adored this series and is undeniable better HxH. Togashi's best work. This is a fact, never to be disputed by opinion or preference. ( ͡° ͜ʖ ͡°)
- Cowboy Bebop: The coolest anime ever. Spike is also one of the coolest characters ever. It ended in one hell of a bang Watanabe, one of the best endings in a fictional story.
- Slam Dunk: Inoue, man I love this guy. Besides being a disgustingly good illustrator, he knows how to tell a story. Started reading R.E.A.L. just recently, fantastic so far. Slam Dunk is the greatest fictional sport story ever told.
- Errr.. I can't do it. From Oda's amazing One Piece, to Hajime No Ippo!, to Major!, to Death Note, to Code Geass, to D-Gray Man, to Rouroni Kenshin, to Monster. Looking at people's list, Akira is a movie. It counts? Because that as well if it does.
It's too difficult to pick 5. You will likely get a different answer if you ask me this question once a month. :\