Top 10 Mecha Manga of 2003
1. Bokurano: Ours
During a summer camp, 15 children, 8 males and 7 females, find a grotto by the sea. Deep within they discover working computers and some electronic equipment, and later the owner, a man called Kokopelli. Kokopelli claimed to be a programmer working on a brand new game, in which a large robot has to defend the Earth against fifteen alien invasions. He persuades the children to test the game and sign a contract. All but one of them signs, barely a moment later they mysteriously awaken on the shore believing what happened was just a dream.
An extra story called Bokurano ~Mō Hitotsu no Bokurano~ (Yet Another Bokurano) will run in Ikki the issue after the end of the main story.
2. Full Metal Panic
A sergeant by the name of Sousuke Sagara is assigned an important task. That of guarding high school girl Chidori Kaname. Sousuke is a military genius, gaining high rank at an early age, but because of his strange upbringing, he lacks social skill. Now, he finds himself as a fish out of water as he attempts to protect a girl from an evil organization and turn in his school work on time.
3. Mobile Suit Crossbone Gundam: Skull Heart
The manga consists of a series of individual stories, centered on the exploits of the Crossbone Vanguard during and three years after the end of the original series, with one exception; the first story is set during the One Year War and deals with Crossbone pilot Umon Samon's youth. The series also features the "return" of Grey Stork, the aged future version of Judau Ashta, who previously appeared in Hasegawa's V Gundam Sidestory manga.
4. Q.ko-chan the Earth Invader Girl
In the near-future on planet Earth, a world gone mad where never-ending war is a fact of life, Kirio is the coolest kid at school. Up in the sky, a giant robot is fighting a fleet of gunships, but the brilliant and distant Kirio is far from fazed—until the battling 'bot makes an unexpected landing in Kirio's front yard and rings the bell. But the worst threat for Kirio could be what stands on the other side of the door: an alien invader robot with the face of an adorable girl!
(Source: Del Rey)
5. Kidou Senshi Gundam Gaiden: Sora, Senku no Hate ni...
This entry is locked and marked for deletion due to being a duplicate entry. You can find the other one here
The story revolves around a second Pegasus class ship named Thoroughbred and its crew. Tasked to intercept a Zeon supply route behind the Moon that leads to Space Fortress Solomon in preparation for "Operation Star One." To accomplish this, the Thoroughbred has been given two gundams piloted by ace pilots Ford Romfellow and veteran Lusse Kessel.
6. Metroid: Samus and Joey
Samus and Joey is a manga series of (at least) 3 issues. It has only been released in Japan, and the storyline occurs several years after Samus Aran's raid on the Space Pirates at Zebes (the events of Metroid and Metroid: Zero Mission). This series introduces the character Joey to the Metroid universe as well as several others such as Dragüd, Diesel, Doruba, Jealousy, Bomad, and the Megaroid.
7. Transformers: The Battle of Star Gate
Near the end of the 20th century, the Transformers form an alliance with the humans. Together they start to develop a large transportation gate named "Trigger" as a symbol of amicability. However, the Decepticons have their eyes on the gate, and so does somebody else.
(Source: Transformers Wiki)
8. Kidou Senshi Gundam Gaiden: Sora, Senku no Hate ni...
The story revolves around a second Pegasus class ship named Thoroughbred and its crew. Tasked to intercept a Zeon supply route behind the Moon that leads to Space Fortress Solomon in preparation for "Operation Star One". To accomplish this, the Thoroughbred has been given two gundams piloted by ace pilots Ford Romfellow and veteran Lusse Kessel.
9. Advance of Z: Flag of Titans
Manga adaptation of the photonovel of the same name.