Quite possibly the most famous would have to be the Animatrix! The Animatrix is one I still have yet to see and this is pretty pathetic considering how much of a Matrix fan I am (I've played several of the games and own all the movies thanks to my dad). The Animatrix is comprised of 9 episodes on one dvd; it was released back in 2003.
Batman Gotham Knight
This is possibly a favorite of mine, and I own the DVD because of how much I wanted to see it. Ha ha. And a really epic cool thing about this DVD is the guy who did the voice for the original Batman is the voice for Batman in this anime! WIN *thumbs up*
# of Episodes: 6
Synopsis: From the producers of Batman Begins and The Dark Knight comes an original animated movie chronicling the establishment and progression of Bruce Wayne into Gotham City's legendary caped crusader through 6 standalone episodes: "Have I Got a Story for You" (the mythos of Batman from the minds of children), "Crossfire" (the initial distrust and the eventual gaining of it from the perspective of the police), "Field Test" (the compassion of Batman, even towards his enemies), "In Darkness Dwells" (tracking down Killer Croc and The Scarecrow to foil his plot of resurgence amongst the villainous of Gotham), "Working Through Pain" (a look back at Bruce's training to manage both the physical and psychological pains he would later endure as Batman), and "Deadshot" (a race against the clock to protect Lt. Gordon from a highly-renowned assassin).
I watched the entire anime series, but wasn't too impressed. The plot was ok and the characters were below average. Frankly, this one failed.
# of Episodes: 24
Synopsis: In 22nd-Century Japan, Masane Amaha, one of the surviving catastrophe that destroyed Tokyo becomes the latest in an ancient line of women-only warriors to wield the mysterious sentient weapon known only throughout history as "the Witchblade". Protecting her little girl, she will face her worst fear ....
More recently Halo Legends was released, but I have yet to see it. Some other adaptations that are either coming out or are out already are Planet Hulk, an X-men anime, Blade, Wolverine and Iron Man.