The armored combat vehicle (or "tank"), is perhaps one of the absolute best weapons to have during a zombie apocalypse. It's armored, it has enough horsepower to penetrate even the densest crowd of hostiles, and its mounted cannon -- and optional side-mounted machine guns -- are perfect for clearing the path. There are several options to choose from. The first is a standard treaded model. These tend to be a bit slower than the others, but the treads are metal and impervious to puncture. They also maintain great grip. The other version, typically used by SWAT teams, is much faster due to a lighter weight and the presence of proper wheels. Without the added weight, however, this tank may become stuck in a large crowd of zombies with no way out.
Weapon tip: Be sure to stock up on both fuel and ammunition. Tanks typically require two or more people to operate, so bring a buddy.