Ryokai said:
Come on guys. Katanas. I mean, how is this even a question?
No. Just no. See, outside of anime and hollywood, the katana is kind of the worst thing you could use for survival-combat. Oh sure, it's plenty sharp and shiny, but it's main advantage is it's insane edge. As it turns out, though, that edge is kinda fragile. Also, zombie canon states that the only way to kill a zombie is to, quoting Sean Of The Dead, "remove the head, or destroy the brain". Now, while one might be able to kill a few zombies with a katana, it'd be both difficult and impractical. I mean, do you have any idea how hard is is to shear through the human skull? I'll give you a hint: it's really, really hard. Not to mention that due to the edge fragility that I mentioned earlier, you could only do it a few times. Frankly, you'd be better off with a golf club...so there.
OP: I'd probably go for a spetsnaz utility shovel. It can be frightfully effective in combat, but it's also made for survival purposes. Otherwise, perhaps a hammer with a lengthened shaft...