Nothing is more fun to read than a quality action manga. Sure there is the big shounen 3 (Bleach, Naruto, and One Piece) and the classic Dragonball Z manga. however, if you are looking for manga recommendations then chances are good that you have already indulged in all of those.
If not, then get out there and read them!
I have also provided recommendations for action animes as well, most of which have very decent mangas as well. However, for the sake of variety, I have left them off this particular list.
In the fashion of science fiction classics, Parasyte follows a quiet and increasingly quick invasion by alien parasites who have descended from the skies and hunger for human flesh. however to survive, they much take control of a human host to survive. Once they have claimed their host, they can mutate the flesh to any form they choose. They can have blades for hands, winged monsters with giant teeth, or super stretching mutants. While most of these parasites choose to hide behind their normal human faces, some aim to destroy humanity. In the case of average high schooler Shinji, the parasite tried to take his body, but became trapped only within his arm. While he battles to keep control of his own body, he must also try to warn humanity of the dangers ahead and fend off attacks from other parasites.
In a world where science fiction is slowly turning into things like The Host by Stephanie Meyer, us science fiction fans must revert back to older stories. Parasyte is kind of like a reincarnation of the Body Snatchers scenario, but because the aliens can mutate flesh so flexibly it is much more action packed. It is a fantastic read for action fans as the parasites like to hunt each other down and battle. Though Parasyte is often forgotten since it is not an ongoing manga. once a manga ends, it tends to fade into the background.
Battle Angel Alita
Below the floating city of Tiphares where the rich live lies the scrap yard below it. The people and cyborgs that live below exist purely on what the city above drops. One day, Doctor Ido stumbles upon the head of a cyborg girl in the trash from the city above. he brings her home and gives her a new body. thus his "daughter" Alita is born. Alita plays the sensitive and dutiful daughter for awhile, but soon a long forgotten fighting technique hidden in her body comes out when he father Doctor Ido's life is threatened. She then decides to become a bounty hunter like her father Ido.
What is truly interesting about Battle Angel Alita is her "power ups" so to speak. For example in Bleach Ichigo gets power ups like his bankai of Hollow form, in Battle Angel Alita, Alita gets whole new bodies. new bodies packed with interesting and inventive weapons. Now getting a new and improved cyborg body is a power up I can really get into. Make sure after finishing Battle Angel Alita you continue onto Battle Angel Alita: Last Order for the story the author wanted to create before he was rushed into ending his series.
During the warring states period of Japan, Shinmen Takezou leaves the village, in which he has always been an outcast for his wild and violent behavior, to join the Toyotomi army with his childhood friend. When the Toyotomi army clashes with the Tokugawa clan at the battle of Sekigahara, they are crushed. Takezou and his friend manage to survive and swear to go onto to do great things with their lives. Vagabond is a fictional retelling of the life of Musashi Miyamoto, who is perhaps the most famous of Japan's sword masters.
While not only exceedingly beautiful, Vagabond is an amazingly gripping story. It really goes into the psychological side of being a swordsman. That is not to say Vagabond is all feelings and emotions, there are plenty of rival warriors for Musashi Miyamoto to battle. Some wield spears, some good old fashioned swords, and some even use a sickle and chain. While his rivals are all great fighters, but they are also expansive and interesting characters which just makes it even more interesting. Usually in action manga the villains are motivated by such petty things as world domination or destruction, it is refreshing to see villains that are not always evil.
Trigun follows the story of super human gunman Vash the Stampede. Vash is a legendary outlaw who often hunted down by outlaws for the $$60,000,000,000 double dollar bounty on his head for the destruction of the city July. Vash the Stampede is notorious for bringing destruction to any place he visit, however this is mostly caused by the bounty hunters on his tail. The truth is Vash is a happy fellow who only wants to foster peace and love.
Everyone loves Trigun, at least the anime anyway. however, the biggest gripe that people have with the Trigun anime is that it kind of ends really vaguely. Trigun Maximum does a better job of explaining all the things that were left open ended in the anime and finally give Trigun the finite ending it needed. Trigun Maximum should have been what the anime followed rather than trying to pack in all this stuff into just one series.
Through a chance encounter with a childhood friend where they rescue a bum off the train tracks, Kei Kurono and his friend die after getting hit by a train. Their story doesn't end there. After a few "lucky" people die, they are transported to a room where they are armed with odd weapons and powerful super suits and told that if they wish to be free and alive again, they must kill aliens.
Gantz is a manga primarily aimed at older audiences, it thrives on two main factors that make people love it--Boobs and violence. The author really loves to draw scanitly clad chicks. However, if you can get past all that it really is an amazing action manga. There are tons of characters that have all sort of cool weapons and powers. Just when you think you cannot love them anymore, the author kills them in the most horrifying ways he can think of. The story seems pretty basic in theory, but the universe really expands in later volumes and explains why these aliens are here and why they have to kill them.
These are just a few of the best selected from my personal manga library. If you have been fortunate to see all of these or have a specific sort of manga in mind, leave a comment. I can give more suggestions if you want them!