Juuki Kouhei Xenon
A dramatic story set in contemporary Japan, about a guy with amnesia, who finds out he was turned into a super-cyborg in a corporate weapon research program. He goes on a mission of revenge. A little shallow, perhaps, but a good example of shounen SF/action manga. The manga ended abruptly, because the magazine it was being serialized in changed its target public and it was decided that Xenon didn't fit in anymore.