/me spits his coffee out at the thought of a Youtube series

zombies have no inherent fighting skill. their only strength is the ability to surround and smother with numbers. we all know that you cannot surround ninjas--they always have an escape route--and plus they are most efficient against slow enemies like zombies. they would easily massacre any number of shambling undead.
and pirates, well they'd just sail out to sea a short distance and blast the (un)living f*** out of the zombie hordes.
edit: oh you were talking about combination zombie/ninja/pirate? i thought you were talking vanilla zombie versus pirates and ninjas, which is no contest.

Ninjas, because:
"You wanna die, Napoleon?" - "Yeah right... Who's the only one here who knows illegal ninja moves from the government?"
-- Napoleon Dynamite

The Doctor > Ninja's > Pirates > Zombies.

Interesting... interesting...

I had this same arguement with my brother awhile back, and while Ninjas was winning, I still sided Pirates because:
A) They have guns
B) Rum, do I need to say anymore
C) They do not fight by the rules, where as the ninjas have a code of honor they must abide by
D) They have awesome hats
E) There is nothing like the spray o' the sea in your face me hearty, argh
F) Pirates were recently on the news for highjacking a cargo ship
Now, ninjas do beat pirates in a number of areas:
A) Stealth
B) Going with the Stealth, they wear black and are quiet, as opposed to noisy sterotypical pirates
C) Shurikens
D) Agile
E) Masters of the Blade
F) THEY ARE LIKE THE F***ING JAMES BOND OF THE ORIENTAL WORLD.
So, six reasons why Pirates rule, and six reasons why Ninjas rule.
I side with PIRATES!!!

You realise The Doctor beats Ninja's and Pirates?

This made me change to the pirate side.

haha

It's so subjective. You may as well ask, "Which is better? Heavy metal or country music?"
But since you asked. Ninja's are probably more useful in a given situation, but pirates are cooler. Eyepatches - enough said!!!

heavy metal. fact. but not by much.

LOL... It was just a hypothetical, but I'd say heavy metal too... By a whole lot though, can't stand country!

I'll pick the one which isn't heavy metal or country.