This is what I'm currently watching on Netflix at the moment. I feel compelled to mention it, simply because it's one of the more engaging animated movies to come out of Japan that I've seen in recent years. I know there's a Gantz anime (and live action film?) and I'm reading the Gantz manga at the moment. This takes some of the ideas from the manga but either it's further along in the overall story or it's a new story in its own right. Or a combination of new material and later stories from the manga, I guess.
The basic premise is that certain people who are dying get selected at the point of their death and are recruited to fight a dizzying array of monsters who have been threatening major Japanese cities. Much carnage ensues. The things that set this film apart are its rather creative and fluid direction, the monster designs and the film's relentless focus on really quite insane action sequences. While one or two of the characters do have their own backstory, the characterisation is minimal but good enough that you get a very firm handle on them without the film slowing down any. It's impressive stuff. I heartily recommend it, if you haven't checked it out already.
Oh, and if you remember when Final Fantasy: The Spirits Within came out and was impressed with the lead character's hair (which reportedly cost $1 million to animate all on its own), then you'll want to check out Gantz: 0 for similar animated coiffure triumphs. And the monster composed entirely of naked female torsos, of course... :D