As some of you Bleach Fans may be aware Tite Kubo (author of Bleach) also did Zombie Powder, I thought that it was a good manga for its short life, due to having been cancelled after 27 chapters.
A good concept and I think it needs a mention somewhere on this forum.
Setting & plot:
Zombie Powder has a futuristic-western setting, similar to that of Trigun. The story begins in 716 A.E. The signs on buildings are in English, but some characters speak Spanish, Russian, and Italian phrases.
Most characters in the manga are "Powder Hunters" searching for the legendary "Zombie Powder". It can make the dead come back to life and make the living immortal, much like the philosopher's stone. However, to obtain the zombie powder one needs to collect the twelve Rings of the Dead. The Rings of the Dead use life energy from anything living to create the Zombie Powder. If a Ring eats a human, that person will fall into a coma. The person will be in that state until he or she dies. Due to the abrupt ending of the manga, the appearance of the Zombie Powder remains unknown, although it may look like white powder that forms a skull with glowing blue eyes (source: Wikipedia/Zombie Powder).
To view Manga:
MSN Group Zombie Powder