I was going to start a Transformers: Prime thread but soneone else beat me to it, I wish I could have commented on it, but anyway...
I loved Code Lyoko, but never got the time to watch it from '03 to '07, I was always working or looking for work, but my love for it revived about a few years ago. It had the inspiration of "Tron", and it had great characters, with awesome stories. Aelita Shaeffer was bar none my favorite character of all. Her sweet princess voice, her "girl next door" type of humble charm, and her cute little melon head.
She was actually an adult, chronologically, but lost about 9 years or so of her life when, at age 12, in 1994, her father brought her with him into the virtual world of Lyoko to hide from the same government officials who snatched her mom. God only knows what happened to her. But she met Jeremy when he found the supercomputer in the abandoned factory, and together with their friends Yumi, Odd, and Ulrich they formed the power team of the Lyoko Warriors. They also had William, who was captured and under control by the evil X.A.N.A., a rogue A.I. program of the virtual world. They all work to rescue William, find Aelita's father, and to defeat the evil X.A.N.A., as well as foil X.A.N.A.'s evil plots to enter our world and destroy it. Such a great TV show ahead of its time. Sadly, they made the mistake of bringing it back, as Code Lyoko Evolution, seeing as how they failed to learn form the mistakes of Teen Titans Go! But I'll always enjoy the classics. I've actually met the voice of Aelita and Jeremy, Sharon Mann, and she's really nice (met her online, but still).