Gundam Seed - I really love this Gundam series. It's really in-depth. Anyway, I have seen this three times over, so I will give you all an in-depth (I'll try) explanation.
Space colonies have spread out in space, and they have created a new type of human - coordinators. These are genetically modified humans, which are born better than a normal human. Normal humans don't get along with coordinators. Asuran (I say Asuran because it looks and sounds better, rather than a lot of people spell how it's said by the Japanese, Aslan) and Kira have known each other since childhood, but they parted because of Asuran's father, which wants his son with coordinators, and Kira goes to Earth. Unexpectantly, they meet on the battlefield, unable to kill each other. They part in different ways, both in a Gundam that Earth created to destroy the Space colonies. But Kira is mistakenly taken in a Gundam, while Asuran has been trained to use a Gundam in space. Throughout the story, we discover heaps of information that I cannot fit in right now. All I can say is grab ahold of it, and watch it!
A side note, I used the subtitled names, because they sound and looks better. I think they shouldn't have changed Asuran to Athlan. I mean, that looks like a retarded name... seriously... I know the Japanese say it like that, but hey, Asuran sounds and looks more decent... eesH!! But also... The mongheads kept the names how the Japanese say it. The Japanese say their 'r's' like an 'l'. But meh, what can I do about it... Just bitch n bicker... which is what I'm doing... :'(